Gram load adjusting system for magnetic head suspensions

ABSTRACT

A system for adjusting the gram load of a suspension with a high degree of accuracy and repeatability includes a clamp, load-engaging member, actuator, laser and control system. The mounting region of a suspension to be adjusted is releasably received and clamped by the clamp. A load beam of the suspension is engaged and supported at adjust positions with respect to the clamp by the load beam-engaging member. The load beam-engaging member is driven and positioned by the actuator. IR light from the laser is directed to the spring region of the suspension by optical fibers. The control system includes a pre-adjust input terminal, memory and a controller. Information representative of a measured pre-adjust fly height gram load value of the suspension is received at the pre-adjust input terminal. Gram load adjust data representative of load beam adjust positions which will cause the suspension W have a desired post-adjust fly height gram load value after the load beam is stressed relieved is stored in the memory. The controller is coupled to the pre-adjust input terminal, actuator, laser and memory, and controls the system by: 1) accessing the memory as a function of the measured pre-adjust fly height gram load value to determine the load beat adjust position which will cause the suspension to have the desired fly height gram load value after the load beam is stressed relieved, 2) actuating the actuator and causing the load beam-engaging member to position the load beam at the adjust position, 3) actuating the laser to stress relieve the spring region of the load beam while the load beam is positioned at the adjust position, and 4) actuating the actuator and causing the load beam-engaging member to release the load beam after the load beam is stress relieved.

REFERENCE TO RELATED APPLICATIONS

Reference is hereby made to the following commonly assigned andcopending applications filed on even date herewith.

1. U.S. patent application Ser. No. 08/655,849 entitled GRAM LOAD,STATIC ATTITUDE AND RADIUS GEOMETRY ADJUSTING SYSTEM FOR MAGNETIC HEADSUSPENSIONS.

2. U.S. patent application Ser. No. 08/657,778 entitled GRAM LOAD,STATIC ATTITUDE AND RADIUS GEOMETRY ESTABLISHING SYSTEM FOR FLATMAGNETIC HEAD SUSPENSIONS.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is a machine for adjusting the characteristics ofsuspensions used in rigid magnetic disk drive head gimbal assemblies. Inparticular, the present invention is a machine for adjusting the gramload of rolled suspensions and head gimbal assemblies.

2. Description of the Related Art

Head gimbal assemblies (HGAs), also sometimes known as head suspensionassemblies (HSAs), are commonly used in rigid magnetic disk drives tosupport magnetic heads in close proximity to the rotating disk surfaces.One such gimbal assembly 10 is illustrated in FIG. 1. As shown, gimbalassembly 10 includes an air bearing head slider assembly 12 mounted to asuspension 14. The suspension 14 includes a load beam 16 having amounting region 18 on its proximal end and a gimbal or flexure 20 on itsdistal end. When incorporated into a disk drive (not shown), themounting region 18 is configured to be mounted to an actuator orpositioning arm which supports the gimbal assembly 10 over the rotatingdisk. A baseplate 21 which includes a mounting boss 23 is typicallywelded to the mounting region 18 to increase the rigidity of themounting region and to provide a mechanism for securely mounting thegimbal assembly to the positioning arm. The load beam 16 is an elongatedand often generally triangularly-shaped member which includes a springregion 24 adjacent to the mounting region 18, and a rigid region 26which extends from the spring region. The spring region 24 of theembodiment shown in FIG. 1 includes a central aperture which forms thespring region into two legs. In this embodiment the flexure 20 ismanufactured as a separate member, and welded to the distal end of therigid region 26. The air bearing head slider assembly 12 contains amagnetic head (not visible in FIG. 1) and is typically bonded to theflexure 20 by adhesive.

During the manufacture of suspensions 14, elongated carrier stripshaving a plurality of flat and unformed load beam blanks extendingtherefrom are chemically etched from thin sheets of stainless steel orother spring material. Carrier strips with flat and unformed flexureblanks are etched in a similar manner from sheets of stainless steel.During subsequent manufacturing operations any side rails 30, wire leadcaptures 32, load point dimples (not visible) and any other structureswhich extend upwardly or downwardly from the generally planar surface ofthe load beam 16 (i.e., in what is known as the z-height direction),along a z-axis are formed on the load beam blanks by mechanical bendingprocedures. Any structures on the flexure blanks requiring z-heightdeformation (e.g., load point dimples, not shown) are formed in asimilar manner. After forming, the flexures 20 are welded to the distalends of the load beams 16. The carrier strip is then cut or detabbedfrom the flexures 20. Baseplates 21 also are welded to the mountingregions 18 of the load beams 16 following the forming operations.

The suspension 14 illustrated and described above is known as athree-piece design in that it includes a load beam 16, flexure 20 andbaseplate 21, all of which are separately fabricated and formed beforebeing welded together. In another suspension design known as a two-piecedesign or integrated gimbal suspension (not shown), the flexure isetched in the distal end of the rigid region of the load beam. Portionsof the integrated gimbal which extend from the planar surface of theload beam in the z-height direction are formed along with otherstructures on the load beam during the forming operation. A baseplate istypically welded to the mounting region after these load beam andintegrated gimbal etching and forming operations.

As shown in FIG. 2, the products of these etching, forming and weldingoperations are carrier strips 34 with generally flat suspensions 14extending therefrom (i.e., the mounting region 18, spring region 24 andrigid region 26 of load beam 16 are generally coplanar and at the samez-height). During subsequent manufacturing operations the spring region24 of each load beam 16 is rolled around a curved mandrel or otherwisebent in such a manner as to plastically bend or deform the springregion. As illustrated in FIGS. 3 and 4, this rolling operation impartsa curved shape to the spring region 24 and causes the flexure 20 to beoffset from the mounting region 18 in the z-height direction when thesuspension 14 is in its unloaded or free state. Equipment and methodsfor performing these rolling operations are generally known anddisclosed, for example, in the Smith et al. U.S. Pat. No. 4,603,567 andthe Hatch et al. U.S. Pat. No. 5,471,734.

As noted above, the suspension 14 supports the slider assembly 12 overthe magnetic disk. In reaction to the air pressure at the surface of thespinning disk, the slider assembly 12 develops a aerodynamic force whichcauses the slider assembly to lift away from and "fly" over the disksurface. To counteract this hydrodynamic lifting force, the head gimbalassembly 10 is mounted in the disk drive with the suspension 14 in aloaded state so the bent spring region 24 of the suspension forces thehead slider assembly 12 toward the magnetic disk. The height at whichthe slider assembly 12 flies over the disk surface is known as the "flyheight." The force exerted by the suspension 14 on slider assembly 12 isknown as the "gram load." High performance disk drive operation requiresthe air bearing head slider assembly 12 to closely follow the rotatingmagnetic disk surface at a constant height and attitude. To meet thiscritical requirement, the gram load of suspensions 14 must be adjustedto a relatively tight specification range (defined in terms of upper andlower range specification gram loads above and below, respectively, thedesired or nominal gram load).

Techniques for adjusting the gram load of suspensions 14 after they havebeen rolled are generally known and disclosed, for example, in the Smithet al. U.S. Pat. No. 4,603,567 and the Schones et al. U.S. Pat. No.5,297,413. Briefly, one such method is known as a "thermal adjust" or"light adjust" technique. A known property of stainless steel memberssuch as load beams is that the force they exert in response to attemptsto bend them can be reduced (stress relieved) through exposure tothermal energy. The functional relationship between the amount of forcereduction and the amount of heat to which a member is exposed can beempirically determined. The light adjust method makes use of thisempirically determined relationship to "downgram" or lower the gram loadof load beams that have been purposely manufactured (e.g., throughrolling operations of the type described above) to have an initial gramload greater than the desired gram load range.

Equipment for performing the light adjust method includes a clamp forclamping the mounting region 18 of the suspension 14 to a fixed base ordatum, and a load cell for measuring the gram load of the suspension. Acomputer controlled actuator moves the load cell into engagement withthe flexure 20 and elevates the flexure to a z-height or offset withrespect to the datum which corresponds to the specified fly height forthe suspension (i.e., the gram load is measured at fly height). Inpractice, the measured gram load quickly rises toward its then-currentvalue as the flexure 20 is elevated. When the measured gram load reachesan upper range specification, the computer actuates or turns on a highintensity infrared lamp to apply heat to the load beam 16. Since theapplied heat reduces the actual gram load of the suspension 14, themeasured gram load quickly peaks. Continued application of heat causesthe measured gram load to decrease with time. The computer deactuates orturns off the lamp when the measured gram load has decreased to apredetermined set point, typically a load between the nominal or desiredgram load and the lower range specification. Once the lamp has beenturned off, the measured decrease in gram load quickly slows and reachesits minimum value (often at a gram load below the lower rangespecification) as the heat in the suspension 14 dissipates. However, asthe load beam continues to cool, the measured gram load increases andstabilizes at an equilibrium or final load value that is preferably wellwithin the specification range, and ideally close to the nominalspecification. The final gram load is also measured following the lightadjust procedure. This measurement is used by the computer tocontinually update the stored model (e.g., the setpoint) of thefunctional relationship between the amount of heat applied (e.g., lampon time) and the gram load reduction, to optimize the accuracy of theresults obtained by the gram adjust procedure.

Computer controlled mechanical bending procedures are also used toadjust the gram load on load beams 16. The mechanical bending methodmakes use of an empirically determined relationship between the amountthat the load beam 16 is mechanically bent and the associated change ingram load. For a range of gram load adjustments that are typicallyperformed by this technique, a simple linear regression line has beenfound to accurately describe this relationship. In practice, thistechnique is implemented by a computer coupled to a stepper motor-drivenbending mechanism and a load cell. A model of the relationship betweenchanges in gram load and the number of motor steps (i.e., the associatedamount or extent of bending required) is stored in the computer. Afterthe then-current gram load of the suspension is measured by the loadcell, the computer calculates the required load correction (i.e., thedifference between the measured and desired loads). The computer thenaccesses the model as a function of the required correction to determinethe number of motor steps required to achieve the required loadcorrection, and actuates the stepper motor accordingly. Once the loadbeam has been bent, the then-current gram load is again measured andused to update the model. Measured data from a given number of the mostrecently executed mechanical bends is used to recompute the regressionline data prior to the execution of the next mechanical bend.

The air bearing head slider assemblies 12 are mounted to the flexure 20,and the lead wires clamped to the load beam 16, after the gram load ofthe suspension has been initially set using methods such as thosedescribed above. Unfortunately, the mechanical handling and assemblyprocedures involved in this manufacturing operation sometimes forces thegram loads of the assembled head suspension assemblies 10 beyond thespecification range. Since the gram load specification is so critical toproper disk drive operation, these out-of-specification head suspensionassemblies cannot be used unless the gram load is readjusted to thespecification range. A machine which uses both the light-adjust andmechanical bending procedures described above to "regram" suspensions isshown in the Schones et al. U.S. Pat. No. 5,297,413.

Another critical performance-related criteria of a suspension isspecified in terms of its resonance characteristics. In order for thehead slider assembly 12 to be accurately positioned with respect to adesired track on the magnetic disk, the suspension 14 must be capable ofprecisely translating or transferring the motion of the positioning armto the slider assembly. An inherent property of moving mechanicalsystems, however, is their tendency to bend and twist in a number ofdifferent modes when driven back and forth at certain rates known asresonant frequencies. Any such bending or twisting of a suspension 14causes the position of the head slider assembly 12 to deviate from itsintended position with respect to the desired track. Since the headsuspension assemblies 10 must be driven at high rates of speed in highperformance disk drives, the resonant frequencies of a suspension shouldbe as high as possible.

As discussed in the Hatch et al. U.S. Pat. No. 5,471,734, the position,shape and size of the roll or bend in the spring region 24 of asuspension 14, sometimes generally referred to as the radius geometry orprofile of the suspension, can greatly affect its resonancecharacteristics. The radius geometry of a suspension must therefore beaccurately controlled during manufacture to optimize the resonancecharacteristics of the part. The radius geometry of a suspension ischaracterized by parameters referred to as offset and bump in the Hatchet al. Patent. However, it is known to define the radius geometry of asuspension using different parameters. By way of example, HutchinsonTechnology Incorporated, the assignee of the present application, hasoften characterized the radius geometry of suspensions such as 14 usinga number of parameters including those referred to as "height" and"depth" or "rippel." As shown in FIG. 4, the height parameter is thez-height distance between the surfaces of the load beam 16 at themounting region 18 and a point on the rigid region 26. The location onthe rigid region 26 at which the height is measured is referenced to theproximal end of the load beam 16 by a distance parameter referred to asthe "height location." The depth is the z-height distance between thesurfaces of the load beam 16 at the mounting region 18 and a point onthe spring region 24. The location on the spring region 24 at which thedepth is measured is referenced to the proximal end of the load beam 16by a distance parameter referred to as the "low point location."Typically, the low point location is the position at which the depth isat its maximum for the suspension 14.

Yet another important performance-related criteria of a suspension 14 isknown as its static attitude. The attitude of a head slider assembly 12refers to the positional orientation of slider assembly with respect tothe surface of the disk over which it is flying. The head sliderassembly 12 is designed to fly at a predetermined orientation (typicallygenerally parallel) with the surface of the disk. Deviations from thisparallel relationship which result in the front and back edges of theslider being at a different heights from the disk (i.e., a rotationabout a y-axis transverse to the longitudinal x-axis of the suspension)are known as pitch errors. Deviations from the parallel relationshipwhich result in the opposite sides of the slider being at differentheights from the disk (i.e., a rotation about the longitudinal x-axis ofthe suspension) are known as roll errors. Any pitch or roll errors inthe desired flying attitude of the slider can degrade the performance ofthe disk drive.

One source of these pitch and roll errors is static attitude errors ofthe suspension. Static attitude errors and the use of static attitudecompensation dimples or protuberances to minimize these errors aredisclosed in the Harrison et al. article The Double Dimple MagneticRecording Head Suspension and its Effect on Fly Height Variability.

There remains a continuing need for improved head suspension adjustingequipment and methods. In particular, there is a need for equipment andmethods for adjusting suspension parameters such as gram load, height orother profile characteristics, roll and/or pitch. Equipment and methodsfor adjusting several of these parameters would be especially desirable.To be commercially viable, any such equipment and methods must capableof achieving a high degree of accuracy and repeatability.

SUMMARY OF THE INVENTION

The present invention is a system for adjusting a suspension parameter,such as gram load, with a high degree of accuracy and repeatability. Oneembodiment of the suspension adjusting system includes a loadbeam-engaging member, an actuator, a heat source and a control system.The load beam-engaging member engages the load beam and supports thehead-receiving region of the load beam at adjust positions with respectto the mounting region. The actuator drives and positions the loadbeam-engaging member. The heat source stress relieves at least thespring region of the load beam. The control system includes a pre-adjustinput terminal, memory and a controller. Information representative of ameasured pre-adjust parameter value of the suspension is received at thepre-adjust input terminal. Parameter adjust data representative ofsuspension parameter adjust positions which will cause the suspension tohave a desired post-adjust parameter value after the load beam is stressrelieved is stored in the memory. The controller is coupled to thepre-adjust input terminal, actuator, heat source and memory, andcontrols the system by: 1) accessing the memory as a function of thepre-adjust parameter value to determined the suspension adjust positionwhich will cause the suspension to have the desired parameter valueafter the load beam is stress relieved, 2) actuating the actuator andcausing the load beam-engaging member to position the load beam at theadjust position, and 3) actuating the heat source to stress relieve atleast the spring region of the load beam while the load beam ispositioned at the adjust position.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view of a head gimbal assembly.

FIG. 2 is an illustration of a carrier strip with a plurality ofgenerally flat suspensions extending therefrom.

FIG. 3 is a side view of the suspension of the head gimbal assemblyshown in FIG. 1, illustrating the profile of the spring region.

FIG. 4 is a detailed side view of the proximal end the suspension shownin FIG. 3, illustrating parameters used to characterize the profilegeometry of the suspension.

FIG. 5 is an isometric view of a first embodiment of the suspensionadjust equipment in accordance with the present invention.

FIGS. 6A-6C are detailed schematic views of a suspension and portions ofthe gram load measurement stations shown in FIG. 5, and illustrate theoperation of the stations to measure the fly height gram load of thesuspension.

FIG. 7 is a detailed side view of the suspension gram adjust stationshown in FIG. 5.

FIG. 8 is a detailed schematic view of a suspension and portions of thesuspension gram adjust station shown in FIG. 7, illustrating thesuspension gram adjust procedure implemented by the suspension gramadjust station.

FIG. 9 is a block diagram of a portion of the electrical subsystem ofthe suspension gram adjust equipment shown in FIG. 5.

FIG. 10 is a flow chart of the gram adjust procedure performed by thesuspension gram adjust station.

FIG. 11 is an isometric view of a second embodiment of the suspensionadjust equipment in accordance with the present invention.

FIG. 12 is a view of the rear side of the suspension clamp assembly ofthe static attitude measure and pitch adjust station shown in FIG. 11.

FIGS. 13A-13C are side views of the static attitude measure and pitchadjust station with portions thereof broken away and shown in section,illustrating the clamp assembly in its transfer, functional clamping andload beam clamping positions, respectively.

FIG. 14 is an isometric view of the base of the suspension clampassembly shown in FIG. 12.

FIG. 15 is a top view of the base assembly of the suspension clampassembly.

FIG. 16 is a sectional side view of the base assembly shown in FIG. 15.

FIG. 17 is a detailed sectional side view of the functional clampingregion and load beam clamping region of the base assembly shown in FIG.16.

FIG. 18 is an isometric view illustrating the lower portions of thefunctional clamp assembly and the load beam clamp assembly of thesuspension clamp assembly shown in FIG. 12.

FIG. 19 is a top view of the clamp frame assembly of the functionalclamp assembly shown in FIG. 18.

FIG. 20 is a top view of the adjustment frame of the load beam clampassembly shown in FIG. 18.

FIG. 21 is a detailed sectional side view of the clamp frame assemblyshown in FIG. 19.

FIG. 22 is a detailed isometric view of the static attitude measure andpitch adjust station.

FIGS. 23A and 23B are detailed sectional side views of the clamp padassembly shown in FIG. 21.

FIG. 24 is a detailed side view of the functional clamp assembly, loadbeam clamp assembly and flexure bend assembly, with portions thereofshown in section.

FIG. 25 is a block diagram of the electrical subsystem of the suspensionadjust equipment shown in FIG. 11.

FIG. 26 is a detailed block diagram of the electrical subsystems of thegram load and profile measure station and the static attitude measureand pitch adjust station shown in FIG. 25.

FIG. 27 is a flow diagram of the static attitude measure and pitchadjust procedures performed by the static attitude measure and pitchadjust station shown in FIG. 11.

FIG. 28 is a side view of portions of the laser adjust station shown inFIG. 11.

FIG. 29 is a detailed top view of portions of the laser adjust stationshown in FIG. 11.

FIG. 30 is a detailed side view of the laser adjust station shown inFIG. 28.

FIG. 31 is a detailed schematic view of a suspension and portions of thelaser adjust station shown in FIG. 11, illustrating the laser adjustprocedure implemented by the laser adjust station.

FIG. 32 is a detailed block diagram of the electrical subsystem of thelaser adjust station shown in FIG. 25.

FIG. 33 is a flow diagram of the laser adjust procedure performed by thelaser adjust station shown in FIG. 11.

FIG. 34 is a view of the rear side of the suspension clamp assembly ofthe static attitude measure station shown in FIG. 11.

FIG. 35 is a side view of the static attitude measure station withportions thereof broken away and shown in section, illustrating theclamp assembly in its measure clamping position.

FIG. 36 is a detailed block diagram of the electrical subsystem of thestatic attitude measurement station shown in FIG. 25.

FIG. 37 is a flow diagram of the static attitude measurement procedureperformed by the static attitude measure station shown in FIG. 11.

FIG. 38 describes the mathematical equations of the algorithm used bythe control system shown in FIG. 25 to control the pitch adjustprocedures performed at the static attitude measure and pitch adjuststation shown in FIGS. 13A-13C, and the laser adjust proceduresperformed at the laser adjust station shown in FIGS. 28-30.

FIG. 39 is a block diagram of suspension adjust equipment in accordancewith a third embodiment of the present invention.

FIG. 40 is a side view of the gram load and height measure station shownin FIG. 39, with portions thereof shown in section.

FIG. 41 is a detailed view of the suspension clamp/actuator assemblyshown in FIG. 40, with portions thereof shown in section.

FIG. 42 is an isometric view of the suspension clamp/actuator assemblyshown in FIG. 40.

FIG. 43 is a detailed sectional view of the clamp/actuator assemblyshown in FIG. 40, illustrating the baseplate clamp.

FIG. 44 is a block diagram of the control system of the gram load andheight measure station shown in FIG. 40.

FIG. 45 is a block diagram of suspension adjust equipment in accordancewith a fourth embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Suspension adjust equipment 100, a first embodiment of the presentinvention, is illustrated generally in FIG. 5. Equipment 100 rolls andgram load adjusts generally flat (i.e., unrolled) suspensions. Asdescribed above in the Background of the Invention section, suspensionsof these types typically have already been formed and are attached tocarrier strips at this stage of their manufacture. For purposes ofexample, therefore, the following description of equipment 100 (as wellas equipment 200, 700 and 900 described below) is provided withreference to carrier strips 34 of suspensions 14 such as those describedabove. However, equipment 100 can also be used to roll and gram loadadjust individual suspensions such as 14 which are not attached tocarrier strips such as 34. Furthermore, equipment 100 can be used togram load adjust head gimbal assemblies such as 10 (i.e., to adjust orreadjust the gram load after a head slider assembly such as 12 has beenbonded to the suspension).

As shown, equipment 100 includes a walking beam 101 which advancescarrier strips 34 (not visible in FIG. 5) through the equipment, andsequentially positions each suspension 14 at a roll station 102, firstgram load measure station 104, gram load adjust station 106, second gramload measure station 108 and an out-of-specification part detab station(not shown). At the roll station 102, the spring region 24 of thesuspension 14 is rolled around a curved mandrel or otherwise bent toimpart the desired radius geometry to the suspension. At the first gramload measure station 104, the suspension 14 is elevated to fly height,and the post-roll fly height gram load of the suspension measured. Asdescribed in greater detail below, a gram load adjust procedure isperformed at station 106 to adjust the gram load of the suspension 14 ifthe post-roll gram load measured at station 104 is outside the desiredspecification range. The post-adjust gram load of the suspension 14 ismeasured at second gram load measure station 108. If the post-adjustgram load of the suspension 14 is outside the desired specificationrange, the suspension is rejected and cut from the carrier strip at theout-of-specification detab station. The carrier strips 34 with theremaining in-specification suspensions 14 are then removed fromequipment 100 and transported to a clean, heat treat and clean station(not shown). Following the cleaning, heat treating and cleaningoperations the suspensions are transported to a final detab stationwhere all the remaining suspensions 14 are cut from the carrier strip34, and subsequently packaged for shipment to customers. In otherembodiments, the suspensions 14 are not heat treated following theiradjustment on equipment 100.

Walking beam 101 can be any conventional or otherwise known mechanismfor transporting and positioning suspensions 14 at stations 102, 104,106 and 108. By way of example, one such walking beam mechanism isdisclosed in the Smith et al. U.S. Pat. No. 4,603,567. The walking beam101 and stations 102, 104, 106 and 108 are mounted to a base 103.

Rolling station 102 can be any conventional or otherwise known mechanismfor bending the spring region 24 of suspension 14 to the desiredprofile. Rolling stations such as 102 are generally known and disclosed,for example, in the Smith et al. U.S. Pat. No. 4,603,567 and the Hatchet al. U.S. Pat. No. 5,371,734. Briefly, the embodiment of rollingstation 102 shown in FIG. 5 includes a base clamp and radius blockmechanism 110, radius block slide 112 and a stepper motor 114 forraising and lowering a roller (not visible). After each suspension 14 isadvanced to rolling station 102 by the walking beam 101, the base clampand radius block mechanism 110 functionally clamps the baseplate 21 ofthe suspension to a base (not visible) with the spring region 24positioned under a curved mandrel (also not visible). The curved mandrelhas a profile which will impart the desired profile to the spring regionof the suspension. Stepper motor 114 is then actuated to raise and drivethe roller through a rolling stroke during which the roller engages androlls the spring region 24 over the mandrel. The extent to which thespring region is rolled over the mandrel (i.e., the length of therolling stroke) affects the gram load of the suspension 14. In oneembodiment of equipment 100, the roll station 102 rolls each suspension14 a constant predetermined amount. Using an interface terminal of theequipment control system (not shown), an operator sets up the rollstation 102 to achieve the desired post-roll gram load (typically apercentage of the desired nominal gram load) in the suspensions 14emerging from roll station 102. The position of the mandrel with respectto the base clamp, and therefore the position of the roll on the springregion 24, a parameter that affects the resonance characteristics of thesuspension, can be adjusted by radius block slide 112. Following therolling procedure the base clamp is opened to release the suspension 14,and the suspension is subsequently transported to first measure station104 by walking beam 101.

First and second gram load measure stations 104 and 108, respectively,can be any conventional or otherwise known mechanism for measuring thegram load of suspensions 14 at fly height. One such gram load measurestation is disclosed, for example, in the Smith et al. U.S. Pat. No.4,603,567. The embodiment of measure station 104 shown in FIG. 5includes load cell 120, elevator 122, elevator actuator 124, steppermotor 126 and base clamp 128. Measure station 108 can be identical tostation 104, and similar features are illustrated with identical butprimed reference numbers (i.e., "x'").

Briefly, after the suspension 14 is advanced to measure station 104 bythe walking beam 101, the base clamp 128 rigidly functionally clamps thebaseplate 21 of the suspension to a base (not visible) with the loadbeam 16 and flexure 20 of the suspension positioned below load cell 120and elevator 122. Stepper motor 126 is then actuated to simultaneouslylower load cell 120 and elevator 122 from a retracted position (shown inFIG. 6A) to an extended position (shown in FIG. 6B) at which the loadcell is located at a relative z-height measurement position with respectto the base which is equal to the specification fly-height of thesuspension 14. As shown in FIG. 6A, when in its retracted position theelevator 122 extends downwardly a greater distance than the load cell120. As the load cell 120 and elevator 122 are lowered, the elevatorwill therefore engage the suspension 14 (typically at a location on therigid region 26 adjacent to flexure 20) before the load cell, andelevate the suspension to a z-height beyond the fly height. After theload cell 120 is lowered to the fly height position, elevator actuator124 is actuated to lift the elevator 122 and gently position flexure 20of the suspension 14 on the load cell (shown in FIG. 6C) for the gramload measurement. This procedure is then repeated in the reverse orderto return the suspension 14 to its free state. Other embodiments ofmeasurement stations 104 and 108 (not shown) do not include an elevator122 or elevator actuator 124, and instead use the load cell 120 toelevate the suspension to the fly-height measurement position. Followingthe gram load measurement procedure the base clamp 128 is opened torelease the suspension 14, and allow the suspension to be transported tothe next station by walking beam 101.

Gram load adjust station 106 can be described in greater detail withreference to FIGS. 5 and 7-10. As shown, the station 106 includes aclamp assembly 130, stepper motor 132 and suspension positioningassembly 134. Clamp assembly 130 includes a fixed base 136 and a movingclamping member 138. Base 136 is rigidly mounted with respect to thewalking beam 101 and has a surface configured to receive and registerthe baseplate 21 of suspension 14. Clamping member 138 is reciprocallydriven between closed and open positions with respect to base 136 insynchronization with the motion of walking beam 101. At the beginning ofa gram adjust procedure, clamping member 138 is in its open position(not shown) spaced from base 136. The walking beam 101 then advances thesuspension 14 to be adjusted into the clamp assembly 130. After thebaseplate 21 has been aligned with the base 136 by the walking beam 101,clamping member 138 is driven to the closed position shown in FIG. 7,functionally clamping the baseplate 21 against the base 136. Themounting region 18 of the suspension 14 is thereby functionally clampedand rigidly held in the adjust station 106 throughout the gram adjustprocedure. Following the completion of the gram adjust procedure theclamping member 138 is driven to its open position to release thesuspension 14 and allow the suspension to be advanced from the station106 by walking beam 101.

Stepper motor 132 and suspension positioning assembly 134 are mounted toa fixed base 140. The stepper motor 132 is fixedly mounted to an upperportion of the base 140. The suspension positioning assembly 134includes a slide mount 142, a support arm 144 and a positioning barassembly 146. Slide mount 142 is mounted to the base 140 for reciprocalmotion in a direction generally parallel to the direction the clampedsuspension 14 can be flexed about its spring region 24 (e.g., about avertical or z-axis in the illustrated embodiment). Support arm 144 ismounted to and extends from slide mount 142. Positioning bar assembly146 is mounted to an end of support arm 144 opposite the slide mount142, and is positioned adjacent to the clamp assembly 130. Stepper motor132 is mechanically connected to and drives the slide mount 142 throughits range of reciprocal motion.

Positioning bar assembly 146 includes a pair of spaced and generallyC-shaped plates 148 having longitudinally extending gaps 150 which opentoward clamp assembly 130. An upper positioning bar 152 extendshorizontally between plates 148 above gap 150. Similarly, a lowerpositioning bar 154 extends horizontally between plates 148 below gap150 and bar 152. Bars 152 and 154 are positioned on assembly 146 atlocations above and below the distal end of the load beam 16 ofsuspensions 14 clamped at and extending from clamp assembly 130. Thepositioning bar assembly 146 is shown at a suspension clamping positionin FIG. 7. In this suspension clamping position gap 150 is aligned withthe clamp assembly 130 enabling suspensions 14 to be advanced into andout of the clamp assembly with the load beam 16 extending between bars152 and 154.

An optical fiber bracket 156 is fixedly mounted adjacent to the base 136of clamp assembly 130. Bracket 156 is configured to receive and hold oneor more optical fibers 158 with the ends 160 of the fibers positioned atlocations directly above the spring region 24 of suspensions 14 clampedat clamp assembly 130. A laser 177 or other source of infrared light(shown in FIG. 9) is coupled to the opposite ends of optical fibers 158.The illustrated embodiment of station 106 includes two optical fibers158 which are mounted within bracket 156 in such a manner that theirends 160 are positioned above the spaced legs of the spring region 24.In general, the ends 160 of fibers 158 are positioned to direct arelatively uniform intensity of infrared light (i.e., heat) over thespring region 24 of the suspension 14. One embodiment of the presentinvention uses a ten watt laser diode from SDL of San Jose, Calif., forlaser 177.

A control system 170 for controlling the operation of gram load adjuststation 106 is illustrated in FIG. 9. As shown, the control system 170includes a digital processor 172 coupled to program memory 174 andinterface terminal 176. The processor 172 is also interfaced to steppermotor 114 of roll station 102, stepper motor 126, elevator actuator 124and load cell 120 of gram load measure station 104, stepper motor 132and a laser 177 of gram load adjust station 106, and stepper motor 126',elevator actuator 124' and load cell 120' of gram load measure station108. A gram adjust program executed by processor 172 to perform gramload adjust procedures is stored in memory 174. Interface terminal 176,which includes a monitor and keypad (not separately shown) is used by anoperator to set up equipment 100 and to monitor the operation of theequipment during production operations.

The gram load adjust procedure is based upon the discovery that the gramload of a suspension can be predictably adjusted to a high degree ofaccuracy, repeatability and stability if the spring region 24 of thesuspension 14 is stressed by lifting or lowering the load beam 16 fromits free state (depending on whether it is desired to upgram or downgramthe suspension) to a predetermined position, and to relieve the stressesby heating the spring region (e.g., through the application of aninfrared laser beam) while the load beam is held in the predeterminedposition. The magnitude of the gram load change generated by thisprocess is dependent upon the amount of the stress to which the springregion 24 is subjected before being stress relieved, and this stresslevel can be controlled by the position of the load beam 16 with respectto its free state position.

Accordingly, adjust data representative of desired fly height gram loadchanges as a function load beam adjust positions is stored in memory174. The load beam adjust positions are positions to which the load beam16 of suspension 14 is driven upwardly by bar 154 or downwardly by bar152 from its free state position. In a preferred embodiment the adjustdata characterizes a linear equation describing gram load changes as afunction of load beam adjust positions. The load beam adjust positionscan be correlated to the number of steps motor 132 must be driven toraise or lower positioning bar assembly 146 from its clamping positionto position the bars 154 and 152 at the desired load beam adjustpositions. Also stored in memory 174 is data representative of thenominal or desired gram load of suspension 14.

FIG. 10 is a flow diagram illustrating the gram load adjust procedureperformed by station 106. The adjust procedure begins with the receiptof data from first gram load measurement station 104 representative ofthe post-roll gram load of the suspension 14 to be gram load adjusted(step 180). The difference between the measured post-roll gram load andthe nominal gram load is then computed to determine the desired gramload change (i.e., the amount of the gram load adjustment to be made bystation 106) (step 182). Processor 172 then accesses the adjust data asa function of the desired gram load change to determine the load beamadjust position which will produce the desired gram load change. In theembodiment described above in which the adjust data is a linearequation, processor 172 computes the load beam adjust position in termsof the required number of steps that motor 176 must be driven to raiseor lower the positioning bar assembly 146 (step 184). Stepper motor 132is then actuated by processor 172 in such a manner as to drive thepositioning bar assembly 146 and cause one of the bars 152 or 154 toposition the load beam 16 at the computed adjust position (step 186).With the load beam 16 held at the adjust position, processor 172actuates laser 177 for an exposure time period and causes the springregion 24 to be heated and stress relieved by the application ofinfrared light directed to the spring region through optical fibers 158(step 188). To complete the adjust procedure, processor 172 turns offlaser 177 at the end of the exposure period and allows the suspension 14to cool to ambient temperature (less than one second is usuallysufficient) (step 190) before again actuating motor 132 and driving thepositioning bar assembly 146 back to the clamping position (step 192).

Control system 170 is set up by an operator through the use of interfaceterminal 176. In one embodiment, the exposure period of laser 177 is setby observing the physical effects of the infrared light on a testsuspension 14. In particular, during exposure trials the exposure periodis increased until the applied heat is sufficiently great to oxidize thesuspension 14, resulting in a "browning" effect on the suspension. Thisprocedure is known as determining the browning threshold. The exposureperiod is then set to a period which is a predetermined length of time(e.g., 50 msec.) less than the browning threshold. This set-up procedurewill result in the spring region 24 being heated to a temperaturebetween about 600°-900° F. (315°-482° C.) during the exposure period.

The gram load adjust data (e.g., the linear equation coefficients forthe preferred embodiment described above) is initially establishedduring set-up procedure in which a number of suspensions 14 having knownpost-roll gram loads (measured at first gram load measurement station104) are driven to different set-up adjust positions and stress relievedat adjust station 106. The post-adjust gram loads of the suspensions 14are then measured at second gram load measurement station 108, and usedby processor 172 to compute the changes in gram load induced by theadjust station 106 at these set-up adjust positions. Processor 172 thengenerates the gram load adjust data by computing a least squares fit(e.g., a Gaussian method) to the measured gram load changes andcorresponding set-up adjust positions. In a similar manner, the adjustdata can be periodically or continually updated by processor 172 duringnormal operation of adjust station 106 on the basis of measureddifferences between the actual post-adjust gram loads and the nominalgram load.

Suspension adjust equipment 200, a second embodiment of the presentinvention, is illustrated generally in FIG. 11. Equipment 200 rolls andadjusts the gram load, radius geometry and static attitude (both pitchand roll) of generally flat (i.e., unrolled) suspensions. As describedabove in the Background of the Invention section, suspensions of thesetypes typically have already been formed and are attached to carrierstrips at this stage of their manufacture. For purposes of example,therefore, the following description of equipment 200 is provided withreference to carrier strips 34 of suspensions 14 such as those describedabove. Portions of equipment 200 are similar to those of equipment 100described above, and these portions are described with reference toidentical but twice primed (i.e., "x"") reference numerals.

As shown, suspension adjust equipment 200 includes a walking beam 101"which advances carrier strips 34 (not visible in FIG. 11) through theequipment. The walking beam 101" sequentially positions each suspension14 at a roll station 102", backbend station 202, gram load and profilemeasure station 204, static attitude measure and pitch adjust station206, laser adjust station 208, static attitude measure station 210 andan out-of-specification part detab station (not shown).

At roll station 102', the baseplate 21 of the suspension 14 is clampedat the base clamp and radius block mechanism 110", and the spring region24 rolled around a curved mandrel to bend the spring region to thedesired profile and impart a desired post-roll gram load to thesuspension. Upon the completion of the rolling operation, the suspension14 is released from the mechanism 110' and transported to backbendstation 202 where the suspension is backbent to reduce its gram load apredetermined amount (i.e., bent a predetermined amount beyond its rangeof elastic deformation in a direction opposite that in which it wasrolled).

Any conventional or otherwise known backbending mechanism can beincorporated into station 202. In the embodiment shown in FIG. 11,backbend station 202 is structurally similar to gram load measurestation 104 described above with reference to adjust equipment 100, butdoes not include a load cell. As shown, backbend station 202 includes anelevator 222, elevator actuator 224, stepper motor 226 and base clamp228. After the suspension 14 is advanced to backbend station 202 by thewalking beam 101", the base clamp 228 functionally clamps the baseplate21 of the suspension to a base (not visible) with the load beam 16 andflexure 20 of the suspension positioned below elevator 222. Steppermotor 226 is then actuated to drive the elevator 222 through a backbendstroke by lowering the elevator from a retracted position to an extendedposition. As it is driven to the extended position the elevator 222 willengage the suspension 14 (typically at a location on the rigid region 26adjacent to flexure 20), and elevate the suspension in a directionopposite to the direction that it was rolled. During the backbendoperation the load beam 16 is elevated beyond its range of elasticdeformation (i.e., beyond the point at which it will "spring back" orreturn to its original free state when released from the elevator) tobend or plastically deform the spring region 24 and reduce thethen-current gram load. The amount of plastic deformation imparted tothe load beam 16 during the backbend operation, and therefore theinduced gram load reduction, is controlled by the extent to which theload beam is backbent (i.e., the length of the backbend stroke ofelevator 222). In one embodiment of adjust equipment 200, the backbendstation 202 backbends each suspension 14 a constant predetermined amount0.3 grams for a suspension having a nominal gram load of two to fivegrams). Using an interface terminal (FIG. 25) an operator set up thebackbend station 202 to achieve the desired post-backbend gram load inthe suspensions 14 emerging from backbend station. Following thebackbending procedures the base clamp 228 is opened to release thesuspension 14, and allow the suspension to be transported to the nextstation by walking beam 101".

Gram load and profile measure station 204 includes a gram loadmeasurement instrument 230 and a z-height measurement instrument 232.Gram load measurement instrument 230 is structurally similar to gramload measure station 104 described above with reference to adjustequipment 100, but does not include an elevator or elevator actuator. Asshown, gram load measurement instrument 230 includes a load cell 234,stepper motor 236 and base clamp 238. After the suspension 14 isadvanced to station 204 by the walking beam 101", the base clamp 238functionally clamps the baseplate 21 of the suspension to a base (notvisible) with the load beam 16 and flexure 20 of the suspensionpositioned below load cell 234. Stepper motor 226 is then actuated todrive the load cell 234 into engagement with the flexure 20 and toelevate the suspension 14 to its specification fly height. A measurementof the post-backbend gram load of the suspension 14 can then be providedby load cell 234.

Z-height measurement instrument 232 is positioned and configured tomeasure the height parameter of suspensions 14 clamped at base clamp238. As described above in the Background of the Invention section, theheight parameter of the suspension can be used to describe the profilegeometry and therefore resonance characteristics of the suspension. Inthe embodiment shown, instrument 232 is an optical point range sensormounted to station 204 between base clamp 238 and load cell 234, andabove suspensions 14 clamped at the base clamp. Optical point rangesensors are generally known and commercially available from a number ofsuppliers including WYKO Corporation of Tucson, Ariz. Briefly, pointrange sensors of this type generate a light beam which is directed to ameasurement target at a non-perpendicular angle. The light beam is thenreflected from the target and directed to a detector. The position atwhich the reflected light beam strikes the detector will vary as afunction of the distance between the instrument 232 and the measurementtarget. On station 204, the instrument 232 is positioned to direct thelight beam to the location on the rigid region 26 of suspension 14 atwhich the height parameter is to be measured (e.g., the heightlocation). Z-height measurement instrument 232 can then provide a heightparameter measurement of the suspension 14 when the suspension iselevated to fly height by the load cell 234. Although not shown, station204 can include alternative measurement instruments for measuring theheight parameter of suspensions 14. Furthermore, additional and/oralternative parameters to height can be used to characterize the profilegeometry of the suspensions 14.

After the gram load and height parameter of the suspension 14 aremeasured, stepper motor 236 is actuated to raise the load cell 234 toits retracted position and return the suspension 14 to its free state.The base clamp 238 is opened to release the suspension 14, and allow thesuspension to be transported to the next station by walking beam 101".

Static attitude measure and pitch adjust station 206 includes suspensionclamp assembly 240, pitch adjust mechanism 242 and static attitudemeasurement instrument 244. After the suspension 14 is advanced tostation 206 by walking beam 101", clamp assembly 240 is actuated anddriven from its open position to a baseplate clamping position at whichthe baseplate 21 of the suspension is functionally clamped and thesuspension elevated to fly height. The static attitude of the flexure 20(both pitch and roll in the illustrated embodiment) is then measured byinstrument 244. After the static attitude is measured, clamp assembly240 is again actuated and driven from the baseplate clamping position toa load beam clamping position. At the load beam clamping position clampassembly 240 fixedly clamps the rigid region 26 of the load beam 16.Pitch adjust mechanism 242 is then actuated to engage and adjust thepitch of the flexure 20. Following these static attitude measurement andpitch adjust procedures, clamp assembly 240 is opened to release thesuspension 14, and allow the suspension to be transported to the nextstation by walking beam 101". In other embodiments (not shown), pitchadjust mechanism 242 is configured to engage and bend the distal end ofload beam 16 to induce pitch changes.

As shown generally in FIGS. 12 and 13A-13C, suspension clamp assembly240 includes a base assembly 246, baseplate clamp assembly 248 and loadbeam clamp assembly 250. Base assembly 246 can be described in greaterdetail with reference to FIGS. 14-16, and includes a base 252 and a flyheight adjustment stop assembly 254. Base 252 is a machined member withan upper surface which includes a clamp assembly guide region 256,baseplate clamping region 258 and load beam clamping region 260. Anelongated channel 262 extends into the clamp assembly guide region 256.Channel 262 has a longitudinal axis which is generally parallel to anaxis extending through clamping regions 258 and 260, a lower surface 264which slopes downwardly with increasing distance from the clampingregions, and a pair of semicircular bearing channels 266 which extendtransversely across the channel at spaced locations. Fly heightadjustment stop assembly 254 includes a pair of roller bearings 268mounted within bearing channels 266, stop block 270, spring 272 andheight adjustment control 274. Stop block 270 has a lower surface 276which is generally parallel to the lower surface 264 of channel 262, anupper surface 278 which is generally parallel to the surface of clampassembly guide region 256, and a central opening 280 which extendsbetween the upper and lower surfaces. The lower surface 276 of stopblock 270 is positioned on roller bearings 268 to enable the stop blockto slide within channel 262, and thereby vary the position of the uppersurface 278 (i.e., the height of the upper surface) with respect to thesurface of base 252. A lower end of spring 272 is hooked around pin 282which is mounted to base 252. An upper end of the spring 272 extendsthrough opening 280 and is hooked around a pin 284 which is mounted tothe stop block 270. Spring 272 therefore biases the stop block 270 in adirection away from clamping regions 258 and 260. Height adjustmentcontrol 274 includes mounting member 286, threaded insert 288, threadedrod 290 and knob 292. Mounting member 286 is positioned on the rear sideof base 252 adjacent the position into which the channel 262 opens, andincludes a bore 294 aligned with the channel. Threaded insert 288 ismounted within the bore 295. Shaft 290 is threadedly mounted withininsert 288 and has a stop end 295 which extends into channel 262. Shaft290 thereby limits the motion of stop block 270 within the channel 262.The height of the upper surface 278 of stop block 270 can therefore beadjusted and set using knob 292 to rotate shaft 290.

Baseplate clamping region 258 and load beam clamping region 260 of thebase 252 can be described in greater detail with reference to FIGS. 14,16 and 17. The baseplate clamping region 260 includes a baseplate clamppad 300, guide pads 302 on opposite sides of the clamp pad and guideridges 304 between the guide pads and the sides of base 252. Baseplateclamp pad 300 is elevated from the surrounding portions of the base 252,and has a generally planar upper surface which is configured to receivethe baseplate 21 of suspensions 14. The guide pads 300 have surfaceswhich slope upwardly toward the clamp pad 300 to guide the baseplate 21of suspensions 14 being advanced to and from the clamp pad by thewalking beam 101". Similarly, the guide ridges 304 have surfaces whichslope upwardly toward clamp pad 300 and guide suspensions 14 beingadvanced to and from the clamp pad.

A registration bore 306 extends into clamp pad 300 and is sized toreceive the mounting boss 23 of suspension 14 clamped to the clamp pad.A rod 308 is mounted within the bore 306 for reciprocal motion, and isbiased upwardly by spring assembly 310. In the embodiment shown, springassembly 310 includes springs 312 and 314 and plunger 316 which areretained in a bore 318 below aperture 306 by screw 320. Spring 314 ispositioned between screw 320 and plunger 316. Spring 312 is positionedbetween the plunger 316 and rod 308. As shown in FIG. 17, springassembly 310 is configured and positioned within bore 318 in such amanner that in its uncompressed or free state the upper surface of rod308 is generally coplanar with the upper surface of clamp pad 300. Whenbaseplates 21 of suspensions 14 are clamped to the clamp pad 300 by thebaseplate clamp assembly 248, the mounting boss 23 will extend into bore306 to accurately position the suspension on the clamp pad. This motionforces rod 308 downwardly and compresses springs 312 and 314. When thebaseplate 21 of the suspension 14 is subsequently released by thebaseplate clamp assembly 248, spring assembly 310 forces rod 308upwardly, thereby lifting the mounting boss 23 out of bore 306 to allowthe suspension to be advanced from the clamp pad 300 by walking beam101".

Load beam clamping region 260 includes a clamp surface 322 and a pair ofguide pads 324 which are positioned on opposite sides of the clampsurface. The guide pads 324 have surfaces which slope upwardly towardthe clamp surface 322 to guide the rigid region 26 of suspensions 14being advanced to and from the clamp surface by the walking beam 101".Clamp surface 322 is recessed from the surfaces of guide pads 324 andincludes a bore 326. As shown in FIG. 17, at shoulder 328 the bore 326extends into a larger diameter bore 330. A plunger 332 which includes arod 334 and piston 336 is mounted for reciprocal motion within bores 326and 330, and is biased upwardly by spring assembly 338. Spring assembly338 includes spring 340, washer 342 and screw 344. Spring 340 isretained within bore 330 in a compressed state to force plunger 332upwardly to the extended position shown in FIG. 17 at which piston 336is engaged with shoulder 328 and the rod 334 extends from aperture 326to a height above the clamp surface 322. When the rigid region 26 ofsuspensions 14 are clamped to the clamp surface 322 by the load beamclamp assembly 250, the plunger rod 334 will be forced into bore 326 bythe rigid region of the suspension. When the rigid region 26 of thesuspension 14 is subsequently released by the load beam clamp assembly250, spring assembly 338 forces plunger 332 upwardly, thereby liftingthe rigid region of the suspension from the clamp surface 322 to allowthe suspension to be advanced by walking beam 101".

Baseplate clamp assembly 248 and load beam clamp assembly 250 can bedescribed generally with reference to FIGS. 12, 13A-13C, 14, 15, and18-22. The baseplate clamp assembly 248 includes a support frame 350,clamping frame assembly 352 and pneumatic actuator 354. Support frame350 supports both the baseplate clamp assembly 248 and load beam clampassembly 250 above the base assembly 246 and includes a pair ofvertically oriented side members 356 and a cross member 358 which issupported by the side members. Actuator 354 is mounted to the uppersurface of the cross member 358 and includes an actuator arm 360 whichextends through an aperture (not visible) in the cross member. Clampingframe assembly 352 includes frame plate 362, yoke 364, elevator assembly366, guide shafts 368 and clamp pad assembly 370. Yoke 364 is mounted tothe upper surface of frame plate 362 by screws 372 and has a slot 374which is sized to receive rod 376. The upper end of rod 376 is fastenedto actuator arm 360 by nuts 378, while the lower end of the rod isfastened to yoke 364 by rings 380 and 382 which extend from and engagethe rod at positions above and below the yoke.

Guide shafts 368 extend from the lower surface of frame plate 362 andare positioned for reciprocal motion in linear bearings 384 which aremounted within apertures 386 in the base 252. In the embodiment shown,two guide shafts 368 are located on opposite sides at the back of theframe plate 362, while one guide shaft 362 is centrally located in atongue 388 extending from the front of the frame plate. A pair of spacedand elongated ridges 390 extend downwardly from the surrounding lowersurface of the frame plate 362. As perhaps best shown in FIG. 18, ridges390 extend between the opposite sides of the frame plate 362, with oneof the ridges being positioned between the pair of guide shafts 368 atthe back of the frame plate and the other located rearwardly of thetongue 388. The guide shafts 368 cooperate with linear bearings 384 toguide frame plate 362 and other components of clamping frame assembly352 through reciprocal baseplate clamping strokes.

Clamp pad assembly 370 can be described with reference to FIGS. 23A and23B. As shown, the clamp pad assembly 370 is mounted within a chamber392 centrally located in the front of the tongue 388 of frame plate 362.Chamber 392 is circular in cross section and has an upper portion 393and a reduced diameter lower portion 395 which are separated by shoulder397. The clamp pad assembly 370 includes outer tube 394, inner tube 396,spring 398, jewel ring 400 and clamp pad 402. Outer tube 394 isconcentrically mounted for reciprocal motion within lower portion 395 ofchamber 392 and has an outwardly extending lip 404 on its upper end andan inwardly extending lip 406 at a position spaced from its lower end.Lip 404 extends into upper portion 393 of the chamber 392 and engagesshoulder 397 to limit the downward motion of outer tube 394. Inner tube396 is mounted within outer tube 394 and has an outwardly extending lip408 on its lower edge. Inner tube 396 is positioned with its lip 408within outer tube 394 and below the inwardly extending lip 406 of theouter tube. The upward motion of the inner tube 396 is thereby limitedwhen its lip 408 engages the lip 406 of outer tube 394. Spring 398 isconcentrically mounted around the inner tube 396 and extends between theinwardly extending lip 406 of the outer tube 394 and a cover plate 410.Cover plate 410 is secured to frame plate 362 by screws 412 (FIG. 19).Spring 398 biases the tubes 394 and 396 and clamp pad 402 to theextended position shown in FIGS. 18 and 23A at which the lower edge oftube 394 projects below the lower surface of frame plate 362.

Clamp pad 402 includes a clamp ball 414, mounting pin 416 and nut 420.The clamp ball 414 is a semi-spherical member having a flat clampingsurface. Pin 416 is fixedly mounted to the semi-spherical surface of theclamp ball 414 and extends upwardly through ring 400 and into the innertube 396. Nut 420 is fastened to the end of pin 416 to hold the pin inthe inner tube 396 with the semi-spherical surface of clamp ball 414engaged with the ring 400 and the flat clamping surface extending belowthe lower edge of tube 394. As shown in FIGS. 23A and 23B, the outerdiameter of the mounting pin 416 is sufficiently less than the innerdiameter of the inner tube 396 to enable the pin to rock or swing withinthe tube while the semi-spherical surface of the clamp ball 414 rotateswithin the ring 400. Ring 400 and the other components of clamp padassembly 370 thereby securely engage the clamp ball 414 while allowingthe flat clamping surface of the clamp ball to engage the mountingregions 18 of suspensions 14 which lack parallelism with the baseplateclamp pad 300 (FIG. 14) when the suspensions are positioned on the clamppad (e.g., due to tolerance variations).

A pair of locating pins 422 having tapered lower edges project from thelower surface of frame plate 362. Locating pins 422 are positionedrearwardly and on opposite sides of the clamp pad assembly 370, and aresized to extend through apertures 35 in carrier strips 34 (FIG. 2) andinto holes 424 of base 252.

Elevator assembly 366 can be described with reference to FIGS. 19 and22. As shown, the assembly 366 includes bracket 440 and elevator pin442. Bracket 440 is fastened to the forward edge of the frame platetongue 388 by screws 444. Elevator pin 442 is mounted within an aperturein the bracket 440 by screw 446, and extends downwardly from thebracket.

As shown in FIGS. 12, 13A-13C, 14, 15, and 18-22, load beam clampassembly 250 includes adjustment frame 450, guide shafts 452 andpneumatic actuators 454. Frame 450 is a generally rectangularly shapedmember having a central opening. A clamp base 456 is mounted to thefront of frame 450. Guide shafts 452 extend from the lower surface offrame 450 and are positioned for reciprocal motion in linear bearings458 which are mounted within apertures 460 in the base 252. Theadjustment frame 450 is positioned below the frame plate 362 of clampingframe assembly 352 and includes a pair of spaced recesses 462 in theupper surface of both sides. The guide shafts 368 of the clamping frameassembly 352 extend through the central opening of adjustment frame 450enabling reciprocal motion of the adjustment frame with respect to theclamping frame assembly. A pair of spaced recesses 464 are located inthe lower surface of both sides of the frame plate 362 of the clampingframe assembly 352, directly above the recesses 462 in the adjustmentframe 450.

Actuators 454 are mounted to the upper surface of frame plate 362 ofclamping frame assembly 352 on its opposite sides between recesses 464,and include actuator arms 466 which extend downwardly through the frameplate and into apertures 468 in adjustment frame 450. Ends of theactuator arms 466 are secured to adjustment frame 450 by screws 470.Springs 472 are mounted in associated recesses 462 and 464 to biasadjustment frame 450 downwardly from the frame plate 362 of the clampingframe assembly 352.

Clamp base 456 includes a load beam clamp pad 474 and guide pads 476 onopposite sides of the clamp pad. The load beam clamp pad 474 is elevatedfrom the surrounding portions of base 456, and has a generally planarsurface with a central bore 478. The planar surface of clamp pad 474 isconfigured to engage the rigid region 26 of suspensions 14. The guidepads 476 have surfaces which slope towards the load beam clamp pad 474to guide the load beam 16 of suspensions 14 being advanced to and fromthe clamp pad by the walking beam 101". As shown in FIGS. 13A-13C and22, bore 478 extends through the load beam clamp pad 474 and base 456,and is aligned with the elevator pin 442. Clamp base 456 also includesan aperture 480 in front of the load beam clamp pad 474. As describedbelow, aperture 480 functions as a shutter for the light beam used tomeasure the static attitude of suspensions 14 clamped by clamp assembly240.

Static attitude measurement instrument 244 is fixedly mounted to asupport frame 484 at a position directly above the aperture 480 in clampbase 456. In the embodiment shown, instrument 244 is an autocollimator.Autocollimators are generally known and commercially available from anumber of sources including Sight Systems of Newburry Park, Calif. andWYKO of Tucson Ariz. Briefly, autocollimator instruments of this typegenerate a collimated beam of light which is directed to a measurementtarget. The light beam is then reflected from the measurement target anddirected to a detector. The incident angle at which the reflected lightbeam strikes the detector will vary as a function of the orientation ofthe surface of the target (i.e., its angle) with respect to the lightbeam. At station 206, instrument 244 is positioned to direct thecollimated light beam to the flexure 20 of suspension 14 throughaperture 480. Instrument 244 can then provide a measurement of thestatic attitude of the flexure 20 when suspension 14 is elevated to flyheight by baseplate clamp assembly 248 in the manner described below.Although not shown, station 206 can include alternative measurementinstruments for measuring the static attitude of flexures 20.

Pitch adjust mechanism 242 includes stepper motor 488 and flexurebending assembly 490. As shown in FIG. 11, the stepper motor 488 isfixedly mounted with respect to base 103' adjacent to suspension clampassembly 240. As shown in FIGS. 13A-13C, 22 and 24, bending assembly 490includes an arm 492 which is mounted to and driven by the stepper motor488. A generally C-shaped member 494 is located on the end of arm 492and includes a pair of flexure-engaging pins 496. One of pins 496extends upwardly from the lower surface of member 494, while the otherextends downwardly from the upper surface of the member. The flexurebending assembly 490 is shown at a suspension transfer position in FIG.13A. In this transfer position the gap between the ends of pins 496 isaligned with the upper surface of rod 334 enabling suspensions 14 to beadvanced into and out of clamp assembly 240 with the flexures 20extending between the pins.

A control system 500 for controlling the operation of adjust equipment200 is illustrated generally in FIG. 25. As shown, the control system500 includes a digital processor 502 coupled to program memory 504 andinterface terminal 506. The processor 502 is also interfaced to theelectrical subsystems (i.e., the electrical components) of each station102", 202, 204, 206, 208 and 210. In particular, processor 502 isinterfaced to roll station electrical subsystem 501, backbend stationelectrical subsystem 503, gram load and profile measure stationelectrical subsystem 505, static attitude measure and pitch adjuststation electrical subsystem 507, laser adjust station electricalsubsystem 509 and static attitude measure station electrical subsystem511. FIG. 26 illustrates in greater detail the electrical subsystems 505and 507 of the gram load and profile measure station 204 and staticattitude measure and pitch adjust station 206, respectively. As shown,the electrical subsystem 505 of the gram load and profile measurestation 204 includes Z-height measurement instrument 232, load cell 234and stepper motor 236. The electrical subsystem 507 of the staticattitude measure and pitch adjust station 206 includes static attitudemeasurement instrument 244, stepper motor 488, baseplate clamp pneumaticvalve 508 and load beam clamp pneumatic valve 510.

A static attitude adjust program executed by the processor 502 toperform static attitude measure and pitch adjust procedures is stored inmemory 504. Baseplate clamp valve 508 couples a source of pressurizedair (not shown) to pneumatic actuator 345 through fittings such as 512(FIG. 12) and hoses such as 514 (not shown in FIG. 12). Similarly, loadbeam clamp valve 510 couples the source of pressurized air to pneumaticactuators 454 through fittings such as 516 and hoses such as 518.

The pitch adjust procedures are based upon the knowledge that the pitchof a flexure 20 of a suspension 14 can be predictably adjusted to a highdegree of accuracy, repeatability and stability by bending the flexureupwardly or downwardly a predetermined amount beyond its range ofelastic deformation (i.e., plastic deformation) with respect to theadjacent rigid region 26 of the load beam 16. The magnitude of thechange in pitch generated by this procedure is dependent upon thedistance or degree to which the flexure 20 is bent within its range ofplastic deformation.

Accordingly, suspension adjust data representative of desired pitchangle changes as a function of flexure bend positions is stored inmemory 504. The flexure bend positions are positions to which theflexure 20 (or load beam 16) of a suspension 14 is driven upwardly ordownwardly by pitch adjust mechanism 242 from its then-current position.The flexure bend positions can be correlated to the number of stepsmotor 488 must be driven to raise or lower bending assembly 490 from itsclamping position to position the pins 496 at the desired bendpositions. Also stored in memory is data representative of the nominalor desired pitch of flexure 20.

FIG. 27 is a flow diagram illustrating the static attitude measure andpitch adjust procedures performed by station 206. The procedure beginswith the transfer of a suspension 14 to be measured and pitch adjustedinto the suspension clamp assembly 240 while the clamp assembly is inthe suspension transfer position shown in FIG. 13A (step 510). Processor502 causes the clamp assembly 240 to be in the suspension transferposition by actuating baseplate clamp valve 508 in such a manner thatpneumatic actuator 354 retracts its actuator arm 360 and drivesbaseplate clamp assembly 248 upwardly to a retracted position.Simultaneously, processor 502 actuates load beam clamp valve 510 in sucha manner that pneumatic actuators 454 retract their actuator arms 466and drive load beam clamp assembly 250 upwardly to a retracted positionagainst the bias forces of springs 472. When the baseplate clampassembly 248 is in the retracted position the clamp pad assembly 370will be biased to its extended position shown in FIG. 23A, while thespring assembly 310 will bias rod 308 at the baseplate clamping region258 on the base 252 to the extended position shown in FIG. 17. The lowersurface and ridges 390 of the baseplate clamp assembly frame plate 362are spaced from the upper surface of the base assembly stop block 270when the baseplate clamp assembly 248 is in the retracted position. Whenthe load beam clamp assembly 250 is in its retracted position theelevator pin extends through bore 478 and beyond the load beam clamp pad474. Spring assembly 338 biases plunger 332 upwardly to an extendedposition shown in FIG. 17 at which it projects beyond the clamp surface322 when the load beam clamp assembly 250 is in the retracted position.As shown in FIG. 13A, when the clamp assembly 240 is in its retractedposition there is sufficient clearance between the baseplate clamp ball414 and the baseplate clamp pad 300, and between the load beam clamp pad474 and the load beam plunger 332, to allow suspensions 14 to beadvanced into and out of the clamp assembly.

After a suspension 14 to be measured and adjusted has been advanced intothe clamp assembly 240, processor 502 actuates baseplate clamp valve 508in such a manner as to cause pneumatic actuator 354 to extend itsactuator arm 360 and drive baseplate clamp frame assembly 352 downwardlythrough a baseplate clamping stroke to the baseplate clamping positionshown in FIG. 13B (step 512). Locating pins 422 extend downwardly fromthe functional clamp assembly frame plate 362 a greater distance thanthe clamp pad assembly 370 in its extended position, so as the baseplateclamp frame assembly 352 is moving downwardly, the locating pins willenter apertures 35 in the suspension carrier strip 34 and register thesuspension 14 over the baseplate clamp pad 300. With continued downwardmotion of the clamp frame assembly 352, the flat lower surface of clampball 414 will engage the mounting region 18 of the suspension 14 andforce the mounting boss 23 into the registration bore 306, therebyforcing rod 308 downwardly against the bias force of spring assembly 310and urging the baseplate 21 of the suspension into contact with theplanar surface of the baseplate clamp pad 300. With still furtherdownward motion of the clamp frame assembly the clamp pad assembly 370is forced toward its retracted position within the frame plate 362against the bias force of spring 398 (FIG. 23B) to securely clamp themounting region 18 of the suspension 14 to the baseplate clamp pad 300(i.e., functionally clamp). This downward motion also causes theelevator pin 442 to engage the rigid region 26 of the load beam 16 andelevate the load beam from its free state.

When the clamp frame assembly 352 is in the baseplate clamping positionthe ridges 390 on the lower surface of the baseplate clamp assemblyframe plate 362 are engaged with the upper surface of the base assemblystop block 270. By adjusting the height of the stop block 270 withrespect to the base 252, the position of the tip of elevator pin 442 canbe set so the elevator pin drives the suspension 14 to fly height whenthe clamp frame assembly 352 is in the baseplate clamping position.

After the baseplate 21 of the suspension 14 is functionally clamped tobase 252 and flexure 20 elevated to fly height processor 502 actuatesstatic attitude measurement instrument 244. As shown in FIG. 13B, staticattitude measurement instrument 244 generates and directs a light beam514 onto the flexure 20 of the suspension. In the embodiment shown thelight beam 514 passes through aperture 480 so that only light reflectedoff the flexure 20 of the suspension 14 is directed back to theinstrument 244. Static attitude data, including both roll datacharacteristic of the pre-adjust fly height roll of the flexure 20 andpitch data representative of the pre-adjust fly height pitch of theflexure is thereby provided to processor 502 by the instrument 244 (step516).

After the static attitude measurement is completed, processor 502actuates load beam clamp valve 510 in such a manner as to causepneumatic actuators 454 to release their actuator arms 466 and allowsprings 472 to force the adjustment frame 450 downwardly through a loadbeam clamping stroke to the load beam clamping position shown in FIG.13C (step 518). As the adjustment frame 450 moves through its clampingstroke the load beam clamp pad 474 engages the rigid region 26 ofsuspension 14 and forces the rigid region downwardly from the fly heightposition at which it was held by the elevator pin 442 and intoengagement with the upper surface of ejector rod 334. With continuedmotion of the adjustment frame 450 the clamp pad 474 clamps the rigidregion 26 of the suspension 14 into clamp surface 322 of the base 252.Ejector rod 334 is forced to a retracted position within base 252 whenthe rigid region 26 of the suspension 14 is clamped to surface 322.

Following the static attitude measurement, processor 502 also computesthe difference between the measured pre-adjust pitch and the nominalpitch to determine the desired pitch change (Dpitch) (i.e., the amountof pitch adjustment to be made by station 206) (step 520). Processor 502then accesses the suspension adjust data as a function of the desiredpitch change to compute or otherwise determine a position referred to as"Bump." Bump is the flexure bend position which will produce the desiredpitch change (step 522). As described in greater detail below, Bump isfunctionally related to the desired changes in the height (Dheight),roll (Droll) and gram load (Dgram) as well as Dpitch. The mathematicalalgorithm used by processor 502 therefore computes Bump as a function ofPitch, Dheight, Droll and Dgram. In the embodiment described herein,processor 502 computes Bump in terms of the required number of stepsthat stepper motor 488 must be driven to raise or lower the bendingassembly 490 from its transfer position. Stepper motor 488 is thenactuated by processor 502 in such a manner to drive the bending assembly490 and position the tips of pins 496 at the desired flexure bendpositions (step 524). Stepper motor 488 is then actuated to drivebending assembly 490 back to the transfer position to complete the pitchadjust procedure (step 526). Flexure 20 is thereby bent to a positionthat will (after the laser adjust procedure performed at station 208 anddescribed below) provide the flexure with the desired or nominal pitchangle when the flexure is elevated to fly height.

The static attitude measurement and pitch adjust procedure is completedwhen the baseplate clamp valve 508 and load beam clamp valve 510 areagain actuated by processor 502 to drive suspension clamp assembly 240back to its suspension transfer position by retracting the clamp frameassembly 352 and the adjustment frame 450 (step 510). As the adjustmentframe 450 is retracted from its clamping position the spring assembly338 will return to its extended position and force plunger 332 upwardlyto lift the rigid region 26 of the suspension 14 from the clamp surface322 of base 252. Similarly, as the clamp frame assembly 352 is retractedfrom its baseplate clamping position the spring assembly 310 will forcerod 308 upwardly to lift the suspension baseplate boss 23 from the bore306 and release the suspension 14 from the clamp assembly 240. Thestatic attitude-measured and pitch-adjusted suspension 14 can then beadvanced from the clamp assembly 240. The static attitude measurementand pitch adjust procedure described above can then be repeated onanother suspension 14.

Laser adjust station 208 can be described with reference to FIGS. 11 and28-31. As shown, laser adjust station 208 includes a baseplate clampassembly 540, load beam positioning assembly 542, load beam clampingassembly 544, optical fibers 546, Z-height measurement instrument 548and gram load measurement assembly 550. Baseplate clamp assembly 540includes a fixed base 552 and a moving clamping member 554. Base 552 isrigidly mounted with respect to the walking beam 101" and has abaseplate clamp pad 556 configured to receive and register the baseplate21 of suspension 14. A spring-biased plunger 558 is located in thecenter of the clamp pad 556. Moving clamping member 554 includes a clamppad 560 and is reciprocally driven between transfer (open) and clamping(closed) positions with respect to base 552 in synchronization with themotion of walking beam 101". At the beginning of a laser adjustprocedure, clamping member 554 is in its transfer position (not shown)spaced from base 552. The walking beam 101" then advances the suspension14 to be adjusted into clamp assembly 540. After the suspensionbaseplate 21 is aligned with the clamp pad 556 by the walking beam 101",clamping member 554 is driven to the clamping position shown in FIGS. 28and 30, functionally clamping the baseplate between clamp pads 556 and560. The mounting region of the suspension 14 is thereby clamped andrigidly held in the laser adjust station 208 throughout the laser adjustprocedure. Following the completion of the laser adjust procedure andpost-adjust Z-height and gram load measurements, the clamping member 554is driven to its transfer position to release the suspension 14 andallow the suspension to be advanced from the laser adjust station 208 bythe walking beam 101".

Z-height measurement instrument 548 can be identical to the instrument232 described above with reference to gram load and profile measurestation 204, and is positioned and configured to measure the heightparameter of suspensions 14 clamped at clamping assembly 540. Gram loadmeasurement assembly 550 includes a load cell 562 having a measurementprobe 582. Drive assembly 564 includes an arm assembly 566, arm mount568 and pneumatic actuator 570. Arm mount 568 is supported by a frame572. Pneumatic actuator 570 is mounted to a frame 574 at a locationabove the arm mount 568, and includes a piston (not visible) connectedby collar 576 to a rod 578 which extends through the arm mount. The endof arm assembly 566 which is located below arm mount 568 is fixedlyconnected to rod 578 and includes guide shafts 580 which extend upwardlyinto linear bearings (not visible) in the arm mount. Load cell 562 ismounted to the end of arm assembly 566 adjacent to clamping assembly 540to position the measurement probe 582 of the load cell above the flexure20 of suspensions 14 clamped to the clamping assembly.

Pneumatic actuator 570 is actuated by control system 500 to drive armassembly 566 and load cell 562 between a retracted position and anextended or measurement position. In the retracted position the loadcell 562 is raised above the load beam positioning assembly 542 toprovide sufficient clearance for the suspensions 14 to be advanced intoand out of the laser adjust station 208 by the walking beam 101". In themeasurement position the load cell 562 is driven downwardly to engagethe measurement probe 582 with the flexure 20 of the suspension 14 andelevate the suspension to fly height. The extent of the downward motionof load cell 562 is limited by the engagement of the collar 576 with astop block 584 on the top of arm mount 568. The vertical position of thestop block 584 with respect to arm mount 568, and therefore the flyheight to which suspensions 14 are elevated when the load cell 562 isdriven to its extended position, can be adjusted through the use ofmicrometer 586.

Load beam clamping assembly 544 includes pneumatic actuator 590, arm 592and bracket 594. Pneumatic actuator 590 is fixedly mounted to frame 596and includes a piston 598 mounted to an end of arm 592 by collar 600.Bracket 594 is mounted to the end of arm 592 opposite collar 600.Optical fibers 546 and load beam clamp pad assembly 602 are mounted tobracket 594. In the embodiment shown, load beam clamp pad assembly 602includes three pogo pins 604 which are biased downwardly toward the loadbeam positioning assembly 542 by springs 606. As perhaps best shown inFIG. 28, optical fibers 546 are mounted to bracket 594 in such a manneras to position the ends of the fibers above the legs of the springregion 24 of the suspension 14 clamped at station 208. Clamp padassembly 602 is mounted to the bracket 594 in such a manner as toposition the assembly above the rigid region 26 of the suspension 14clamped at station 208. Pneumatic actuator 590 is actuated by controlsystem 500 and drives the arm 592, optical fibers 546 and clamp padassembly 602 between a retracted position and an extended or load beamclamping position.

Load beam positioning assembly 542 includes stepper motors 610A-610C andpositioning pin assemblies 612A-612C which are driven by the motors.Positioning pin assemblies 612A-612C include arms 614A-614C connected tothe respective motors 610A-610C, and positioning pins 616A-616C whichare mounted to and extend upwardly from the ends of the arms. As perhapsbest shown in FIGS. 29 and 31, the arms 614A-614C are configured toposition the pins 616A-616C below the rigid region 26 of suspensions 14clamped at station 208. In the particular embodiment shown, pins 616Aand 616B are positioned below a central portion of the rigid region 26along a generally transverse load beam axis, and symmetrically spacedfrom the central longitudinal load beam axis. Pin 616C is positioned onthe central longitudinal axis below a rear portion of the rigid region26 and adjacent to the spring region 24. Stepper motors 610A-610C drivepositioning pin assemblies 612A-612C between retracted positions andextended adjust positions. When in the retracted positions, positioningpins 616A-616C are at positions which provide sufficient clearance forsuspensions 14 to be advanced into and out of station 208.

The electrical subsystem 509 of laser adjust station 208 is illustratedgenerally in FIG. 32. As shown, the electrical subsystem 509 includesstepper motors 610A-610C, load cell 562, Z-height measurement instrument548, load beam clamp valve 618, load cell elevator valve 620 and diodelaser 622. Load beam clamp valve 618 couples a source of pressurized air(not shown) to pneumatic actuator 590 through hoses such as 624 (FIG.11). Similarly, valve 620 couples the source of pressurized air topneumatic actuator 570 through the hoses 624.

The laser adjust procedure performed by station 208 is based upon thediscovery that the height (profile geometry), roll and gram load ofsuspension 14 can be predictably adjusted to a high degree of accuracy,repeatability and stability by driving the rigid region 26 to apredetermined position and orientation from its free state to stress thespring region 24, and to relieve the stresses by heating the springregion (e.g., through the application of an infrared laser beam) whilethe load beam is held in the predetermined position and orientation. Themagnitude of the Z-height, roll and gram load change generated orinduced by this process is dependent upon the amounts and distributionof the stress to which the spring region 24 is subjected before beingstress relieved, and this stress level and distribution can becontrolled by the position and orientation of the load beam with respectto its free state position and orientation.

Accordingly, adjust data representative of desired fly height gram load,height and roll changes as a function of load beam adjust positions andorientations is stored in the memory 504 of control system 500. The loadbeam adjust positions and orientations are positions and orientations towhich the load beam 26 is driven by positioning assembly 542 from itsfree state position. In the preferred embodiment described herein theadjust data characterizes a series of linear and nonlinear equationsdescribing gram load, height and roll changes as a function of adjustpositions and orientations. The load beam adjust positions are planarpositions established by the positioning pins 616A-616C (i.e., the tipsof positioning pins 616A-616C define a planar adjust position). Statedanother way, in the embodiment described herein the positioning pins616A-616C are driven to positions which support the load beam 26 ofsuspensions 14 in planar positions and orientations during the laseradjust procedures. The adjust position of each pin 616A-616C can becorrelated to the number of steps motors 610A-610C, respectively, aredriven from their retracted positions to position the pins at thedesired adjust positions. Data representative of desired or nominalvalues of fly height gram load, height and roll for suspensions 14 arealso stored in memory 504.

FIG. 33 is a flow diagram illustrating the laser adjust procedureperformed by station 208 on suspensions 14 clamped at clamping assembly540. The procedure begins with the transfer of a suspension 14 to beheight, gram load and roll adjusted into the clamping assembly 540 whenthe clamping member 554 is in its transfer position, and closing theclamping member to functionally clamp the mounting region 18 to base 552between clamp pads 560 and 556 (step 630). The differences (i.e.,desired changes) between the measured pre-adjust and desired or nominalgram load, height, roll and pitch values (Dgram, Dheight, Droll andPitch, respectively) are computed by processor 502 (step 632). Processor502 then accesses the adjust data as a function of the desired changesin gram load, height, roll and pitch to compute or otherwise determinethe adjust positions of pins 616A-616C (step 634). Stepper motors610A-610C are then actuated by processor 502 in such a manner as todrive the positioning pin assemblies 612A-612C upwardly and position thepins 616A-616C at the adjust positions (step 636).

After the positioning pin assemblies 612A-612C are driven to theiradjust positions, processor 502 actuates load beam clamp valve 618 insuch a manner as to cause pneumatic actuator 590 to drive arm 592 andthe load beam clamp pad assembly 602 on the end thereof from itsretracted position to the load beam clamping position shown in FIGS. 28and 30 (step 638). The pogo pins 604 of clamp pad assembly 602 arelocated directly above positioning pins 616A-616C. As the clamp padassembly 602 is lowered from its retracted position the pogo pins 604will engage the upper surface of the rigid region 26 of suspension 14and force suspension into the adjust position with the lower surface ofthe rigid region engaged with the tips of positioning pins 616A-616C.The springs 606 apply a sufficiently great bias force to the pins 604that the pogo pins will force the rigid region 26 of the suspension 14into engagement with positioning pins 616A-616C. With continued downwardmotion of the clamp pad assembly 602 after the pogo pins have forced theload beam 16 into the adjust position, the pogo pins will retract intobracket 594 against the bias force of the springs 606.

With the load beam 26 held at the adjust position, processor 502actuates laser 622 for an exposure time period and causes the springregion 24 to be heated and stress relieved by the application ofinfrared light directed to the spring region through the optical fibers546 (step 640). Laser 622 is turned off by the processor 502 at the endof the exposure period and the suspension allowed to cool (about 30msec. in one embodiment) (step 642). To complete this laser adjustprocedure processor 502 actuates load beam clamp valve 618 and steppermotors 610A-610C to drive the clamp pad assembly 602 and positioning pinassemblies 612A-612C to their retracted positions (step 644).

Post-adjust gram load and z-height (for profile geometrycharacterization) measurements are taken at station 208 following thelaser adjust procedure. Following the laser adjust procedure theelevator valve 620 is actuated by processor 502 to drive load cell 562downwardly to the measurement position at which the suspension 14 iselevated to fly height. Processor 502 then takes a post-adjust flyheight gram load measurement from the load cell 562 (step 646). With thesuspension elevated to fly height processor 502 also actuates theZ-height measurement instrument and takes a post-adjust radius regionprofile measurement (step 648). Following these post-adjust measurementsthe processor 502 actuates the elevator valve 620 to drive the load cellback to its retracted position (step 650). Clamping member 554 is thendriven to its transfer position (opened) to allow the adjusted andmeasured suspension 14 to be advanced out of the clamping assembly 540by walking beam 101" (step 652).

Static attitude measurement station 210 can be described with referenceto FIGS. 11, 34 and 35. As shown, station 210 includes suspension clampassembly 660 and static attitude measurement instrument 662. Staticattitude measurement instrument 662 can be identical in structure,function and operation to instrument 244 described above with referenceto station 206. With the exception of the differences describedimmediately below, suspension clamp assembly 660 can be identical instructure, function and operation to suspension clamp assembly 240described above with reference to station 206, and similar features areidentified by common but primed (i.e., "x'") reference numerals. Thedifferences between clamp assemblies 660 and 240 are due to the factthat no flexure pitch adjustment is performed at static attitudemeasurement station. No load beam or adjustment clamping operations aretherefore performed by clamp assembly 660, so the adjustment frame 450'is not used and is fixedly mounted to the frame plate 362' of clampingframe assembly 352' by bolts 664. Unlike suspension clamp assembly 240of station 206, suspension clamp assembly 660 does not include pneumaticactuators such as 454 or biasing springs such as 472 for driving theframe plate 450' to a load beam clamping position.

FIG. 36 is a block diagram of the electrical subsystem 511 of staticattitude measurement station 210. As shown, electrical subsystem 511includes static attitude measurement instrument 662 and functional clampvalve 666, both of which are interfaced to processor 502.

FIG. 37 is a flow diagram illustrating the static attitude measurementprocedure performed by station 260. The procedure begins with thetransfer of a suspension 14 to be measured into the suspension clampassembly 660 while the clamp assembly is in the suspension transferposition (not shown) (step 668). Processor 502 causes the clamp assembly660 to be in the suspension transfer position by actuating load beamclamp valve 666 in such a manner that pneumatic actuator 354' retractsits actuator arm 360' and drives load beam clamp assembly 248' upwardlyto a retracted position. After a suspension 14 to be measured has beenadvanced into the clamp assembly 660, processor 502 actuates load beamclamp valve 666 in such a manner as to cause pneumatic actuator 354' toextend its actuator arm 360' and drive load beam clamp frame assembly352' downwardly to the baseplate clamping position shown in FIG. 35(step 670). When the clamp frame assembly 352' is at its clampingposition the elevator pin 442' engages the rigid region 26 of the loadbeam 16 and elevates the load beam 16 from its free state to fly height.

After the baseplate 21 of the suspension 14 is functionally clamped tobase 252' and its flexure 20 elevated to fly height processor 502actuates static attitude measurement instrument 662. As shown in FIG.35, instrument 662 generates and directs a light beam onto the flexure20 through aperture 480'. Post-adjust static attitude data, includingboth roll data characteristic of the post-adjust fly height roll of theflexure 20 and pitch data representative of the post-adjust fly heightpitch of the flexure is thereby provided to processor 502 by theinstrument 662 (step 672). The post-adjust static attitude measurementis completed when the load beam clamp valve 666 is again actuated byprocessor 502 to drive suspension clamp assembly 660 back to itssuspension transfer position by retracting the clamp frame assembly 352'(step 668). The static attitude-measured suspension 14 can then beadvanced from the clamp assembly 660, and the static attitudemeasurement procedure described above repeated on the next suspension.

If the post-adjust gram load, height or static attitude of thesuspension 14 is outside the desired specification ranges, thesuspension is rejected and cut from the carrier strip at theout-of-specification detab station. The carrier strips 34 with theremaining in-specification suspensions 14 are then removed fromequipment 200 and transported to a cleaning station (not shown).Following the cleaning operations the suspensions 14 are transported toa final detab station where all the remaining suspensions 14 are cutfrom the carrier strip 34, and subsequently packaged for shipment tocustomers. In other embodiments, the suspensions 14 are also heattreated following their adjustment on equipment 200.

A detailed description of the algorithm executed by processor 502 tocontrol the pitch adjust procedure at station 206 and the gram load,height and roll adjust procedure (i.e., the laser adjust procedure) atstation 208 follows. The mathematical equations included in thealgorithm and referred to below are set out in FIG. 38. As mentionedabove, the changes in pitch, gram load, height and roll that made atstations 206 and 208 are designated Pitch, Dgram, Dheight and Droll,respectively. These parameters are computed by processor 502 inaccordance with Equations 1-4. The embodiment of the algorithm describedherein makes use of four response variables designated "Load," "Bias,""Pivot" and "Bump." These response variables are defined in Equations5-9 in terms of the relative pin positions of the pitch adjust mechanism242 of station 206 and the load beam positioning assembly 542 of station208 to minimize the amount of coupling or dependence.

Equations 9-12 are used to calculate Pivot, Bias, Load and Bump,respectively. As described in FIG. 38, in addition to the desiredchanges in pitch, gram load, height and roll, Equations 9-12 make use ofweight factors "A"-"N" as well as computed constants "Constant", "α","p", "q", "Det", "u" and "v" which are set out in Equations 13-19. Thenumerical system represented by Equations 1-19 has been formatted sothat there is only one set of real roots, and two pair of conjugateimaginary sets. This numerical system can be solved directly using aconvolute transform, eliminating the need for any type of convergencecomputational technique.

It has been observed that there are subtle differences in the way thatdifferent types or designs of suspensions 14 respond to the pitch adjustprocedure performed at station 206. To account for these differences,the exponent in Equation 12 used to calculate Bump includes the variable"Power". This variable Power is set for each type of suspension 14during a setup procedure performed by processor 502. For example, whenadjusting a Type 850 suspension 14 available from Hutchinson Technologyincorporated, Power is set equal to three. When adjusting a Type 1650suspension 14 available from Hutchinson Technology Incorporated, Poweris set equal to thirteen.

During the setup procedure processor 502 executes a teach routine toestablish weight factors A-N. Processor 502 performs a full factorialwith Load, Bias and Pivot during the setup procedure. Bump is variedindependently of Load, Bias and Pivot during this setup procedure.During this setup procedure measured pre-adjust and post-adjust valuesof gram load, height, pitch and roll, as well as the associated adjustpositions are stored and processed by Gaussian regression to computeinitial values of weight factors A-N. By way of example, representativenumerical values of weight factors A-N for a Hutchinson TechnologyIncorporated Type 850 suspension are listed below in Table 1. Weightfactors A-N, and therefore the computed constants as well, are alsoupdated on the basis of the differences between the desired gram load,height, pitch and roll of the suspensions 14, and the measuredpost-adjust values of gram load, height, pitch and roll, respectively,and on the basis of the associated adjust positions (i.e., correlationdata). In one embodiment, the weight factors A-N are continually updatedfollowing the adjustment and post-adjust measurement of each suspension14 using the historical correlation data from a predetermined number(e.g., eighty in one embodiment) of the most recently processedsuspensions 14.

TABLE 1

A=9.59655×10²

B=4.224

C=-33.378

D=18.357

E=-5.73643×10²

F=-94.246

G=-56.948

H=-0.6379

I=11.59

J=-0.05835

K=0.1114

L=0.57972

M=-3.457

N=5.304

Suspension adjust equipment 700, another embodiment of the presentinvention, is illustrated generally in FIG. 39. As shown, equipment 700includes a roll module 702 and an adjust module 704. Roll module 702includes a pitch stabilize station 706, roll station 708 and backbendand gram load measure station 710, all of which are interfaced tocontrol system 712. Adjust module 704 includes gram load and heightmeasure station 714, static attitude measure station 715, pitch adjuststation 716, laser adjust station 717, static attitude measurementstation 718 and gram load and height measure station 719, all of whichare interfaced to control system 726.

A walking beam (not shown in FIG. 39) such as that described above withrespect to suspension adjust equipment 100 advances carrier strips 34 offormed suspensions 14 (also not shown) through the roll module 702, andsequentially positions each suspension 14 at stations 706, 708 and 710.After being positioned at each station 706, 708 and 710 the baseplate 21of suspension 14 is functionally clamped at its mounting region 18 andprocessed before being unclamped and advanced to the subsequent station.The overall operation of the roll module 702, as well as that of itsstations 706, 708 and 710, is coordinated and controlled by controlsystem 712.

At the pitch stabilization station 706 the flexure 20 of the suspension14 is heated to relieve any residual stresses. In one embodiment (theindividual components of which are not shown), this stress relievingheating operation is performed by subjecting the flexure 20 to infraredlight generated by a laser diode and directed to the flexure by one ormore optical fibers. Control system 712 can be set up in a mannersimilar to that of station 106 of adjusting equipment 100 describedabove to apply sufficient stress relieving heat, but not brown, theflexure 20. The rigid region 26 of the suspension 14 can also be heatedto relieve residual stresses in a manner similar to that of the flexure20.

At roll station 708 the spring region 24 of the suspension 14 is rolledaround a curved mandrel to form the spring region. Rolling station 708can be structurally and functionally similar to the rolling station 102of adjust equipment 100 described above.

At backbend and gram load measurement station 710 the suspension 14 isbackbent a predetermined set amount to reduce and thereby help stabilizethe gram load of the suspension. The backbending mechanism (notseparately shown) at station 710 can be structurally and functionallysimilar to the mechanism used to perform the backbend operation atbackbend station 202 of adjust equipment 200 described above. Station710 also includes a gram load measurement instrument (not separatelyshown in FIG. 40) for measuring the post-roll gram load of thesuspensions 14. The post-roll gram load measurements made at station 710are used during the roll station 708 setup procedure. The gram loadmeasurement instrument at station 708 can be structurally andfunctionally similar to that at station 714 and described in greaterdetail below.

Adjust module 704 also includes a walking beam (not shown) for advancingthe carrier strips 34 of suspensions 14 (also not shown) through themodule and for sequentially positioning each suspension at stations714-719. After being positioned at each station 714-719 the suspension14 is functionally clamped at its mounting region 18 and processedbefore being unclamped and advanced to the subsequent station. Theoverall operation of the adjust module 704, as well as that of itsstations 714-719 is coordinated and controlled by control system 726.

At the gram load and height measure station 714 the suspension 14 iselevated to fly height. The pre-adjust height (i.e., a profile geometryparameter) and pre-adjust gram load of the suspension 14 are thenmeasured through the use of a load cell and Z-height measurementinstrument (not shown in FIG. 39), respectively.

At the static attitude measure station 715 the suspension is againelevated to fly height. The pre-adjust static attitude of the flexure 20(both roll and pitch) are then measured through the use of a staticattitude measurement instrument (not shown in FIG. 39).

At the pitch adjust station 716 the rigid region 26 of the suspension 14is rigidly clamped. The flexure 20 is then plastically bent upwardly ordownwardly by a pitch adjust mechanism (not shown in FIG. 39) to adjustthe pitch of the flexure. The pitch adjust mechanism can be structurallyand functionally similar to pitch adjust mechanism 242 of adjustequipment 200 described above.

At the laser adjust station 717 a load beam positioning assembly (notshown in FIG. 39) orients and positions the rigid region 26 of thesuspension 14 at an adjust position to stress the spring region 24. Thespring region 24 is then stress relieved by the application of infraredlight generated by a laser and directed to the spring region throughoptical fibers. The gram load, height and roll of the suspension 14 arethereby adjusted. The load beam positioning assembly can be structurallyand functionally similar to load beam positioning assembly 542 of adjustequipment 200 described above. The laser and optical fibers can besimilar to the fibers 546 and laser 622 of adjust equipment 200. Thealgorithm used by control system 726 to control the pitch adjustprocedure performed at station 716 and the gram load, height and rolladjust procedure at station 717, and to update the adjust data, can besimilar to the algorithm implemented by processor 502 of adjustequipment 200 described above.

At the static attitude measure station 718 the suspension 14 is againelevated to fly height. The post-adjust static attitude of the flexure20 (both roll and pitch) are then measured through the use of a staticattitude measurement instrument (not shown in FIG. 39). Static attitudemeasurement station 718 can be structurally and functionally similar tostation 715.

At the gram load and height measure station 719 the suspension 14 iselevated to fly height. The post-adjust height and post-adjust gram loadof the suspension 14 are then measured through the use of a load celland Z-height measurement instrument (not shown in FIG. 39),respectively. Gram load and height measure station 724 can befunctionally and structurally similar to station 714.

Although not shown in FIG. 39, adjust module 704 also includes a rejectsuspension detab station to which the suspensions 14 are advanced by thewalking beam after being measured at station 719. The reject suspensiondetab station is interfaced to and controlled by control system 726.Out-of-specification suspensions 14 (i.e., suspensions with measuredpost-adjust static attitude, height or gram load outside a predeterminedrange of the desired static attitude, height and gram load) are cut fromthe carrier strip 34 at this station. Detab stations of this type areknown and disclosed, for example in the Smith et al. U.S. Pat. No.4,603,567. The carrier strips 34 with the in-specification suspensions14 are then manually removed from the walking beam at the gram load andheight measure station 719 and transported to a final detab station. Allthe remaining suspensions 14 are cut from the carrier strips 34 at thefinal detab station, and subsequently packaged for shipment tocustomers.

Gram load and height measure station 714 can be described in greaterdetail with reference to FIG. 40. As shown, station 714 includes asuspension clamp/actuator assembly 728, gram load measurement assembly730 and Z-height measurement instrument 732. Gram load measurementassembly 730 is mounted to a support frame 736 on base 734 and includesstepper motor 738, slide mount 740, support arm 742 and load cell 744.Slide mount 740 is mounted with respect to the support frame 736 forreciprocal motion along a vertical axis and is driven through its rangeof motion by stepper motor 738. Support arm 742 is mounted to andextends from the slide mount 740. Load cell 744 is mounted to andextends downwardly from the end of the support arm 742, and ispositioned directly above the flexure 20 of suspensions 14 clamped atclamp/actuator assembly 728. In response to control signals from controlsystem 726 (FIG. 39), stepper motor 738 drives the load cell 744 betweena retracted or transfer position and a fly height measurement position.In the transfer position the load cell 744 is raised sufficiently highthat it does not interfere with suspensions 14 being advanced into andout of the suspension clamp/actuator assembly 728. When lowered to themeasurement position the load cell 744 engages the flexure 20 andelevates the suspension 14 to fly height to enable fly height gram loadmeasurements by the load cell. Adjustment mechanism 746 can be used toadjust the measurement position of the load cell 744.

Z-height measurement instrument 732 is mounted to base 734 at a positionbelow the rigid region 26 of suspensions 14 clamped at clamp/actuatorassembly 728. Instrument 732 is positioned and configured to measure theheight parameter of suspensions 14 after the suspensions have beenelevated to fly height by the gram load measurement assembly 730.Optical point range sensors such as instrument 232 described above withreference to adjust equipment 200 can be used for this purpose. In oneembodiment, instrument 732 is an LC 2430 point range sensor availablefrom Keyence of Osaka, Japan.

Suspension clamp/actuator assembly 728 can be described with referenceto FIGS. 40-43. As shown, the assembly 728 is mounted above the walkingbeam feed shaft 729 and includes base assembly 750, locating pin blockassembly 752, functional clamping block assembly 754, load beam actuatorblock assembly 756 and cam assembly 758. Base assembly 750 include arigidly mounted base 760 with a baseplate clamping region which includesa baseplate clamp pad 762. A registration bore 766 extends into theclamp pad 762 and is sized to receive the mounting boss 23 of asuspension 14 clamped to the clamp pad. A lifting rod 764 is mountedwithin the bore 766 for reciprocal motion, and is biased upwardly byspring 768. Guide rods 770 are rigidly mounted to base assembly 750 andextend upwardly and downwardly from the base 760.

Cam assembly 758 includes a splined shaft 776 mounted for rotationwithin base assembly 750. A locating cam 778, clamping cam 780 andactuator cam 782 are spline mounted to and rotated by shaft 776.

Locating pin block assembly 752 is positioned below the base assembly750 and includes a guide block 772 mounted for reciprocal verticalmotion on guide rods 770 by linear bearings 774. The upper surface ofguide block 772 includes a recess 784 in which a cam follower 786 isrotatably mounted to the guide block. The cam follower 786 is positionedfor engagement by the locating cam 778 of cam assembly 758. Tensionsprings (not shown) on the opposite sides of the guide block 772 areconnected between the guide block 772 and base assembly 750 to force thelocating pin block assembly 752 upwardly and its cam follower 786 intoengagement with the locating cam 778.

A locating pin assembly 788 including support arm 790 and pins 792 (onlyone is visible in FIGS. 40, 41 and 43) is mounted to the front of guideblock 772. Pins 792 extend upwardly through apertures in base 760 whichare aligned with the apertures 35 in the suspension carrier strip 34when the baseplate 21 of the suspension is positioned over the clamp pad762. The support arm 790 and pins 792 are driven through a carrier striplocating stroke between extended and retracted positions in response tothe rotation of shaft 776. Locating cam 778 and cam follower 786cooperate to control the position of pins 792 within their locatingstroke.

Functional clamping block assembly 754 is positioned immediately abovethe base assembly 750 and includes a guide block 794 mounted forreciprocal vertical motion on guide rods 770 by linear bearings 796. Thelower surface of the guide block 794 includes a recess 798 in which acam follower 800 is rotatably mounted to the guide block. The camfollower 800 is positioned for engagement by the clamping cam 780 of camassembly 758. Tension springs 802 on the opposite sides of the guideblock 794 are connected between the guide block 794 and base assembly750 to force the clamping block assembly 754 downwardly and its camfollower 800 into engagement with the clamping cam 780.

A baseplate clamping assembly 804 including support arm 806 and clamppad assembly 808 is mounted to the front of guide block 794. Clamp padassembly 808 is mounted within a chamber 810 in the support arm 806 at aposition directly above the clamp pad 762 on base 760. As perhaps bestshown in FIG. 43, the clamp pad assembly 808 includes a spring 812,jewel ring 814 and clamp pad 816. Clamp pad assembly 808 is structurallyand functionally similar to the clamp pad assembly 370 of adjustequipment 200 described above. The clamp pad assembly 808 is driventhrough a clamping stroke between a transfer position and a baseplateclamping position in response to the rotation of shaft 776. Clamping cam780 and cam follower 800 cooperate to control the position of the clamppad assembly 808 within its clamping stroke.

Load beam actuator block assembly 756 is positioned immediately abovethe functional clamping block assembly 754 and includes a guide block820 mounted for reciprocal vertical motion on guide rods 770 by linearbearings 822. The lower surface of the guide block 820 includes a recess824 in which a cam follower 826 is rotatably mounted to the guide block.The cam follower 826 is positioned for engagement by the actuator cam782 of cam assembly 758. Tension springs 828 on the opposite sides ofthe guide block 820 are connected between the guide block 820 and baseassembly 750 to force the actuator block assembly 756 downwardly and itscam follower 826 into engagement with the actuator cam 782.

A load beam actuating member or assembly such as elevator assembly 830is mounted to the front of guide block 820. Elevator assembly 830includes a support arm 832 which extends from the guide block 820 andpositions elevator pin 834 over the rigid region 26 of suspensions 14clamped between the clamp pad 762 and the clamp pad assembly 808. Theelevator assembly 830 is driven through an elevator stroke between aretracted position and an elevated position in response to the rotationof shaft 776. Actuator cam 782 and cam follower 826 cooperate to controlthe position of the elevator assembly 830 within its elevator stroke.

As shown diagrammatically in FIG. 40, suspension clamp/actuator assembly728 includes a control system 840 which interfaces the walking beam feedshaft 729 to the cam assembly 758. The control system 840 is shown ingreater detail in FIG. 44 to include optical encoder 842, motorcontroller 844 and motor 846. The optical encoder 842 is opticallycoupled to walking beam feed shaft 729 in a conventional manner andgenerates electrical position signals representative of the position ofthe feed shaft. Motor controller 844 is a conventional programmablemotor controller which is configured to receive the position signalsfrom encoder 842. As shown, motor controller 844 is also interfaced tothe control system 726 of the adjust module 704. The control system 726provides control commands to motor controller 844 and receivesinformation from the motor controller. The control system 726 canthereby synchronize the operation of the functions it controls (i.e, theoperation of gram load measurement assembly 730 and Z-height measurementinstrument 732 at station 714) to the operation of suspensionclamp/actuator assembly 728.

Motor controller 844 is programmed to generate motor drive signals as afunction of the position signals received from encoder 842 and controlcommands received from control system 726. The motor drive signalsgenerated by the controller 844 are applied to motor 846 in aconventional manner (e.g., through a motor driver, not shown). Therotation of cam shaft 776, and therefore the carrier strip guidingoperations performed by locating pin block assembly 752, the baseplateclamping operation performed by functional clamping block assembly 754,and the load beam elevating operation performed by load beam actuatorblock assembly 756 are thereby synchronized to the rotation of feedshaft 729. The relative motion and timing of the carrier strip guidingoperations performed by locating block assembly 752, the baseplateclamping operation performed by functional clamping block assembly 754and the load beam elevating operation performed by load beam actuatorblock assembly 756 are synchronized by the locating cam 778, clampingcam 780 and actuator cam 782. Since the speed at which suspensions 14are advanced through the stations 714-719 of the adjust module 704 isdirectly related to the speed at which the walking beam feed shaft 729is rotated, the control system 840 of station 714 and the control system726 of the adjust module 704, and the operations controlled by thesecontrol systems, are effectively synchronized to the speed at whichsuspensions 14 are being advanced through the adjust module.

Gram load and height measure station 714 operates in the followingmanner. As the walking beam is advancing a suspension 14 into thesuspension clamp/actuator assembly 728, control system 840 causes theshaft 776 to be rotated to a position at which cams 778, 780 and 782drive the locating pin block assembly 752, clamping block assembly 754and the load beam actuator block assembly 756, respectively, to theirextended positions. After the mounting region 18 of the suspension 14 ispositioned over the clamp pad 762, and with continued rotation of shaft776 the locating cam 778 causes the pins 792 are driven through acarrier strip locating stroke toward its extended position.Simultaneously, the clamping cam 780 causes the clamp pad assembly 808to be driven through its clamping stroke toward the clamping position.The motion of the locating pins 792 leads the motion of the clamp padassembly 808 so the pins extend through the apertures 35 of the carrierstrip and thereby locate the carrier strip with the baseplate 21 of thesuspension 14 aligned with the clamp pad 762, before the clamp padassembly 808 engages the mounting region 18 of the suspension. After thesuspension 14 has been located and the clamp pad assembly 808 engagedwith the mounting region 18, the locating cam 778 and clamping cam 780cause the pins 792 and clamp pad assembly to be driven to and held attheir extended positions. The mounting region 18 and baseplate 21 of thesuspension 14 are thereby rigidly clamped to base 760 between the clamppad 762 and clamp pad assembly 808.

Actuator cam 782 causes the elevator assembly 830 to be driven throughits elevator stroke toward the elevated position while the clamp padassembly 808 is being driven toward its clamping position, but themotion of the elevator assembly lags the motion of the clamp padassembly. After the suspension 14 is clamped, the elevator pin 834 willengage the load beam 16 and elevate the load beam to a position slightlybeyond fly height when the elevator pin has been driven to its elevatedposition. As the elevator pin 834 is being driven to its elevatedposition the motor controller 844 provides instructions to controlsystem 726 of the adjust module 704. In response to the instructions thecontrol system 726 generates control signals which cause the steppermotor 738 to drive the load cell 744 its fly height measurementposition. Once the load cell 744 is at the fly height measurementposition the actuator cam 782 causes the elevator pin 834 to be driven ashort distance toward its retracted position to gently position theflexure 20 of the suspension 14 onto the load cell. A measurement of thefly height gram load of the suspension 14 is then taken. Control system726 also causes the Z-height measurement instrument 732 to initiate ameasurement of the Z-height of the suspension 14 while the suspension iselevated to fly height by the load cell 744. With further rotation ofthe shaft 776 following the fly height gram load and Z-heightmeasurements, the above-described actions of the locating block assembly752, clamping block assembly 754 and load beam actuator block assembly756 are effectively repeated in reverse order to return the locatingpins 792, clamp pad assembly 808 and load cell 744 to their retractedpositions. The measured suspension 14 can then be advanced to the staticattitude measure station 715, and another suspension advanced into thegram load and height measure station 714.

Suspension clamp/actuator assemblies and associated control systemssimilar to those described immediately above (i.e., similar to assembly728 and system 840) can be included in the other stations of roll module702 and adjust module 704. One embodiment of adjust system 700, forexample, includes suspension clamp/actuator assemblies and controlsystems similar to 728 and 840, respectively, at stations 710 and714-719. Given the modular characteristics of the suspensionclamp/actuator assembly 728 and control system 840, they can beefficiently adapted for use in the other stations of adjust system 700.For example, the suspension clamp/actuator assembly 728 can be adaptedfor use in other stations by mounting different cams such as 778, 780and 782 on shaft 776 to accommodate varying timing requirements. Thecontrol system 840 can also be programmed to accommodate therequirements of the other stations.

The load beam actuator block assembly 756 of the suspensionclamp/actuator assembly 728 can also be adapted for use on the otherstations of adjust equipment 700. For example, in place of the elevatorassembly 830, the embodiment of the suspension clamp/actuator assemblyof the pitch adjust station 716 includes a load beam actuator blockassembly having a load beam clamp pad functionally similar to the clamppad 474 of station 206 of adjust equipment 200. The base assembly of thesuspension clamp/actuator assembly of the pitch adjust station 716includes an adjustment clamping region, plunger and spring assemblyfunctionally similar to the clamping region 260, plunger 332 and springassembly 338 of the station 206 of adjust equipment 200. The load beamactuator block and base of the suspension clamp/actuator assembly ofstation 716 are thereby configured to rigidly clamp the rigid region 26of suspensions 14 during the pitch adjust procedures performed by thestation.

In place of the elevator assembly 830, the embodiment of the suspensionclamp/actuator assembly of the laser adjust station 717 includes a loadbeam actuator block assembly having a clamp pad assembly structurallyand functionally similar to the clamp pad assembly 602 of the laseradjust station 208 of adjust equipment 200. The load beam actuator blockof the suspension clamp/actuator assembly of station 714 is therebyconfigured to cooperate with the load beam positioning assembly ofstation 720. In this embodiment of laser adjust station 717, the opticalfibers are fixedly mounted to the base at a location directly below thespring region 24 of suspensions 14 clamped at the station.

Suspension adjust equipment 900, another embodiment of the presentinvention, is illustrated generally in FIG. 45. As shown, equipment 900includes static attitude measure station 901, pitch adjust station 902,laser adjust station 903, static attitude measure station 904 and gramload and height measure station 905, all of which are interfaced tocontrol station 906. A walking beam (not shown in FIG. 45) such as thatdescribed above with respect to suspension adjust equipment 100 advancescarrier strips 34 of formed suspensions 14 (also not shown) throughequipment 900, and sequentially positions each suspension 14 at stations901-905. After being positioned at each station 901-905 the suspension14 is functionally clamped at its mounting region 18 and processedbefore being unclamped and advanced to the subsequent station. Theoverall operation of stations 901-905 is coordinated and controlled bycontrol system 906.

At the static attitude measurement station 901 the pre-adjust staticattitude of the flexure 20 (both pitch and roll) is measured through theuse of a static attitude measurement instrument (not shown in FIG. 45).Static attitude measure station 901 can be structurally and functionallysimilar to station 715 of the suspension adjust equipment 700 describedabove (but the suspension is not elevated to fly height for themeasurement).

At the pitch adjust station 902 the rigid region 26 of the suspension 14is rigidly clamped. The flexure 20 is then plastically bent upwardly ordownwardly by a pitch adjust mechanism (not shown in FIG. 45) to adjustthe pitch of the flexure. Pitch adjust station can be structurally andfunctionally similar to station 716 of the suspension adjust equipment700 described above.

At the laser adjust station 903 a load beam positioning assembly (notshown in FIG. 45) orients and positions the rigid region 26 of thesuspension 14 at an adjust position to stress the spring region 24. Thespring region 24 is then stress relieved by the application of infraredlight generated by a laser and directed to the spring region throughoptical fibers. Since the suspension was not rolled (i.e., was notprocessed at a roll station such as 708 of adjust equipment 700), a gramload and height are imparted to the suspension 14 at laser adjuststation 903. In effect, the laser adjust station 903 induces a radiusinto the spring region 24. The roll of the suspension 14 is alsoadjusted at station 903. With the exception of changes in the algorithmused to perform the laser adjust procedure and described below, laseradjust station 903 can be structurally and functionally similar tostation 717 of the suspension adjust equipment 700 described above.

At the static attitude measure station 904 the suspension 14 is elevatedto fly height. The post-adjust static attitude of the flexure 20 (bothroll and pitch) is then measured through the use of a static attitudemeasurement instrument (not shown in FIG. 45). Static attitude measurestation 904 can be structurally and functionally similar to station 901.

At the gram load and height measure station 905 the suspension 14 isagain elevated to fly height. The post-adjust gram load and post-adjustheight (i.e., a profile geometry characteristic) of the suspension 14are then measured through the use of a load cell and Z-heightmeasurement instrument, respectively (not shown in FIG. 45). Gram loadand height measurement station 905 can be structurally and functionallysimilar to station 719 of adjust equipment 700.

The control system 906 of adjust system 900 can be similar in structureand operation to the control system 500 of adjust equipment 200.Accordingly, the algorithm executed by control system 906 is similar tothe algorithm executed by control system 500. The main differencebetween the algorithm executed by control system 900 is that unlikecontrol system 500, the algorithm does not make use of a pre-adjust gramload or a pre-adjust height since stations 902 and 903 process unrolledsuspensions 14. The measured pre-adjust gram load and pre-adjust heightused by the algorithm (i.e., through Equations 2 and 3 in FIG. 38) aretherefore effectively zero.

The suspension adjust equipment of the present invention offersimportant advantages. In particular, suspension characteristics such asgram load, static attitude and profile geometry can be efficientlyestablished and/or adjust to a high degree of accuracy andrepeatability. The characteristics of suspensions processed by theinvention also exhibit a high degree of stability.

Although the present invention has been described with reference topreferred embodiments, those skilled in the art will recognize thatchanges can be made if form and detail without departing from the spiritand scope of the invention. In particular, systems 100, 200, 700 and 900can be used to adjust individual suspensions and head gimbal assemblies.

What is claimed is:
 1. A head suspension adjusting system for adjustinga parameter of a suspension of the type having a load beam with a springregion, a mounting region on a proximal end of the load beam and ahead-receiving region on a distal end of the load beam, the systemincluding:a load beam-engaging member for engaging the load beam andsupporting the head-receiving region of the load beam at adjustpositions with respect to the mounting region; an actuator for drivingand positioning the load beam-engaging member; a heat source forapplying heat to at least the spring region of the load beam; apre-adjust input terminal for receiving information representative of ameasured pre-adjust parameter value of the suspension; memory forstoring parameter adjust data representative of suspension parametervalue changes as a function of load beam adjust positions; and acontroller coupled to the pre-adjust input terminal, actuator, heatsource and memory, for actuating the actuator as a function of themeasured pre-adjust parameter value and the parameter adjust data, andfor actuating the heat source, to adjust the parameter of the suspensionto a desired parameter value.
 2. The suspension adjusting system ofclaim 1 wherein the system is configured to adjust the gram load of thesuspension to a desired gram load value, and wherein;the input terminalreceives pre-adjust gram load measurement data representative of themeasured pre-adjust gram load value of the suspension at a predeterminedoffset height; the memory includes gram load adjust data representativeof offset height gram load value changes as a function of load beamadjust positions; and the controller includes:first means fordetermining a desired gram load value change as a function of themeasured pre-adjust gram load value and the desired gram load value, andfor accessing the memory as a function of the desired gram load valuechange to determine the suspension adjust position; second means foractuating the actuator and causing the load beam-engaging member toposition the load beam at the adjust position; and third means foractuating the heat source to stress relieve at least the spring regionof the load beam while the load beam is positioned at the adjustposition.
 3. The suspension adjusting system of claim 2 wherein:thesystem further includes a post-adjust input terminal for receivingpost-adjust gram load measurement data representative of the measuredpost-adjust gram load value of the suspension at a predetermined offsetheight; and the controller further includes fourth means for causing thegram load adjust data to be updated as a function of the differencebetween the measured post-adjust gram load value and the desired gramload value.
 4. The suspension adjusting system of claim 3 and furtherincluding one or more gram load measuring instruments coupled to thepre-adjust input terminal the post-adjust input terminal, for measuringthe pre-adjust and post-adjust gram load values of the suspension at thepredetermined offset height.
 5. The suspension adjusting system of claim2 wherein the actuator includes a stepper motor.
 6. The suspensionadjusting system of claim 5 wherein the load beam-engaging memberincludes:a support arm mounted to and driven by the stepper motor; andone or more positioning bars mounted to the support arm.
 7. Thesuspension adjusting system of claim 5 wherein the memory stores thegram load adjust data as a function of stepper motor positionsrepresentative of load beam adjust positions.
 8. The suspensionadjusting system of claim 2 wherein the memory stores the gram loadadjust data as a linear equation describing gram load value changes as afunction of the load beam adjust positions.
 9. The suspension adjustingsystem of claim 2 wherein:the system further includes a clamp forreleasably receiving and clamping the mounting region of the suspension;and the actuator drives and positions the load beam-engaging member withrespect to the clamp.
 10. The suspension adjusting system of claim 2wherein the controller further includes fourth means for actuating theactuator and causing the load beam-engaging member to release thesuspension after the load beam is stress relieved.
 11. The suspensionadjusting system of claim 1 wherein the heat source includes:a laser;and one or more optical fibers for directing light from the laser to thesuspension.
 12. The suspension adjusting system of claim 11 wherein theoptical fibers have ends positioned to direct light from the laser tothe spring region of the suspension.
 13. The suspension adjusting systemof claim 1 wherein the system is configured for adjusting rolledsuspensions.
 14. The suspension adjusting system of claim 1 wherein thesystem is configured to adjust the gram load of the suspension to adesired gram load value, and wherein:the input terminal receivespre-adjust gram load measurement data representative of the measuredpre-adjust gram load value of the suspension at a predetermined offsetheight; the memory includes gram load adjust data representative ofoffset height gram load value changes as a function of load beam adjustpositions; and the controller includes:first means for accessing thememory to determine the suspension adjust position which will cause thesuspension to have the desired gram load after the load beam is stressrelieved; second means for actuating the actuator and causing the loadbeam-engaging member to position the load beam at the adjust position;and third means for actuating the heat source to stress relieve at leastthe spring region of the load beam while the load beam is positioned atthe adjust position.
 15. The suspension adjusting system of claim 14wherein the controller further includes fourth means for actuating theactuator and causing the load beam-engaging member to release the loadbeam after the load beam is stress relieved.
 16. The suspensionadjusting system of claim 14 wherein:the system further includes apost-adjust input terminal for receiving post-adjust gram loadmeasurement data representative of the measured post-adjust gram loadvalue of the suspension at a predetermined offset height; and thecontroller further includes fourth means for causing the gram loadadjust data to be updated as a function of the difference between themeasured post-adjust parameter value and the desired parameter value.17. The suspension adjusting system of claim 1 wherein the system isconfigured to adjust the static attitude roll of the suspension and thememory stores roll adjust data representative of suspension adjustpositions which will cause the suspension to have a desired post-adjuststatic attitude roll value after the load beam is stress relieved. 18.The suspension adjusting system of claim 1 wherein the system ifconfigured to adjust the profile geometry of the suspension and thememory stores radius geometry adjust data representative of suspensionadjust positions which will cause the suspension to have a desiredpost-adjust profile geometry value after the load beam is stressrelieved.
 19. A head suspension adjusting system for adjusting aparameter of a suspension of the type having a load beam with a springregion, a mounting region on a proximal end of the load beam and ahead-receiving region on a distal end of the load beam, the systemincluding:a load beam-engaging member for engaging the load beam andsupporting the head-receiving region of the load beam at adjustpositions with respect to the mounting region; an actuator for drivingand positioning the load beam-engaging member; a heat source for stressrelieving at least the spring region of the load beam; a pre-adjustinput terminal for receiving information representative of a measuredpre-adjust parameter value of the suspension; memory for storingparameter adjust data representative of suspension parameter adjustpositions which will cause the suspension to have a desired post-adjustparameter value after the load beam is stress relieved; and a controllercoupled to the pre-adjust input terminal, actuator, heat source andmemory, including:first means for accessing the memory as a function ofthe measured pre-adjust parameter value to determine the suspensionadjust position which will cause the suspension to have the desiredparameter value after the load beam is stress relieved; second means foractuating the actuator and causing the load beam-engaging member toposition the load beam at the adjust position; and third means foractuating the heat source to stress relieve at least the spring regionof the load beam while the load beam is positioned at the adjustposition.
 20. The suspension adjusting system of claim 19 wherein thecontroller further includes fourth means for actuating the actuator andcausing the load beam-engaging member to release the load beam after theload beam is stress relieved.
 21. The suspension adjusting system ofclaim 19 wherein:the system further includes a post-adjust inputterminal for receiving post-adjust parameter measurement datarepresentative of the measured post-adjust parameter value of thesuspension; and the controller further includes fourth means for causingthe parameter adjust data to be updated as a function of the differencebetween the measured post-adjust parameter value and the desiredparameter value.
 22. The suspension adjusting system of claim 19 whereinthe system is configured to adjust the gram load of the suspension, andthe memory stores gram load adjust data representative of suspensionadjust positions which will cause the suspension to have a desiredpost-adjust gram load value after the load beam is stress relieved. 23.The suspension adjusting system of claim 19 wherein the system isconfigured to adjust the static attitude roll of the suspension, and thememory stores roll adjust data representative of suspension adjustpositions which will cause the suspension to have a desired post-adjustroll value after the load beam is stress relieved.
 24. The suspensionadjusting system of claim 19 wherein the system is configured to adjustthe profile geometry of the suspension, and the memory stores profilegeometry adjust data representative of suspension adjust positions whichwill cause the suspension to have a desired post-adjust profile geometryvalue after the load beam is stress relieved.
 25. A head suspension gramload adjusting system for adjusting the gram load of a suspension of thetype having a load beam with a spring region, a mounting region on aproximal end of the load beam and a head-receiving flexure on a distalend of the load beam, the system including:a clamp for releasablyreceiving and clamping the mounting region of the suspension; a loadbeam-engaging member for engaging the load beam and supporting the loadbeam at adjust positions with respect to the clamp; an actuator fordriving and positioning the load beam-engaging member; a heat source forstress relieving at least the spring region of the load beam; apre-adjust input terminal for receiving information representative of ameasured pre-adjust fly height gram load value of the suspension; memoryfor storing gram load adjust data representative of load beam adjustpositions which will cause the suspension to have a desired post-adjustfly height gram load value after the load beam is stress relieved; and acontroller coupled to the pre-adjust input terminal, actuator, heatsource and memory, including:first means for accessing the memory as afunction of the measured pre-adjust fly height gram load value todetermine the load beam adjust position which will cause the suspensionto have the desired fly height gram load value after the load beam isstress relieved; second means for actuating the actuator and causing theload beam-engaging member to position the load beam at the adjustposition; third means for actuating the heat source to stress relieve atleast the spring region of the load beam while the load beam ispositioned at the adjust position; and fourth means for actuating theactuator and causing the load beam-engaging member to release the loadbeam after the load beam is stress relieved.
 26. The suspensionadjusting system of claim 25 wherein:the memory includes gram loadadjust data representative of fly height gram load value changes as afunction of load beam adjust positions; and the first means of thecontroller includes means for determining a desired gram load valuechange as a function of the measured pre-adjust gram load value and thedesired gram load value, and for accessing the memory as a function ofthe desired gram load value change to determine the suspension adjustposition.
 27. The suspension adjusting system of claim 25 wherein:thesystem further includes a post-adjust input terminal for receivingpost-adjust gram load measurement data representative of the measuredpost-adjust fly height gram load value of the suspension; and thecontroller further includes fifth means for causing the gram load adjustdata to be updated as a function of the difference between the measuredpost-adjust gram load value and the desired gram load value.
 28. Thehead suspension gram load adjusting system of claim 27 and furtherincluding one or more gram load measuring instruments coupled to thepre-adjust input terminal and the post-adjust input terminal, formeasuring the pre-adjust and post-adjust fly height gram load values ofthe suspension.
 29. The head suspension gram load adjusting system ofclaim 25 wherein the actuator includes a stepper motor.
 30. The headsuspension gram load adjusting system of claim 29 wherein the loadbeam-engaging member includes:a support arm mounted to and driven by thestepper motor; and one more positioning bars mounted to the support arm.31. The head suspension gram load adjusting system of claim 29 whereinthe memory stores the gram load adjust data as a function of steppermotor positions representative of load beam adjust positions.
 32. Thehead suspension gram load adjusting system of claim 25 wherein thememory stores the gram load adjust data as data representative of alinear equation.
 33. The head suspension gram load adjusting system ofclaim 25 wherein the heat source includes:a laser; and one or moreoptical fibers for directing light from the laser to the suspension. 34.The head suspension gram load adjusting system of claim 33 wherein theoptical fibers have ends positioned to direct light from the laser tothe spring region of the suspension.
 35. The suspension adjusting systemof claim 25 wherein the system is configured for adjusting rolledsuspensions.